Right off the bat, your best bet is to find a smaller sized OG jacket (meaning one actually produced in 1990) on eBay.
Here's what I know, as well as my own personal rant, about the 2017 AJ V Vault (a.k.a. 1990 Jordan Flight Warmup Retro) line:
For one, the remastered apparel never came in a men's small in any color. The smallest size was medium and the biggest was XXL.
For two, as far as I know, the black and red jacket is sold out in every store in the world that it was released to. Unless some store took back a very late and very recent return, which is highly unlikely. I'm pretty aware of this, as at one point I kept tabs on EVERY store that I found that carried these. Which wasn't many, and to make things more complicated, the release was almost a whole year ago. If there are more than 2 dozen total surviving complete sets of the black/red Vault suit in each individual size (M, L, XL, XXL) left in the world, I'd be surprised.
This was a completely bungled release from the start. It seems it was always meant to be a somewhat limited release, but early last summer in an online Jordan.com article AND on Nike.com, Jordan specifically advertised that the black/red jacket and pants would be an upcoming apparel release available on NDC the same day as the release of the all red AJ V "Flight Suit" sneakers. In fact, the all red, all black premium, white/Cement, and all blue AJ V's from last summer were directly inspired by and designed to match with each Vault suit of the same corresponding color. Ultimately, neither the black/red nor red/black suits EVER at any time actually released on NDC. Instead, they trickled the black ones out low key throughout the summer to a (very) few Tier Zero accounts around the world. Each shop didn't usually get all sizes at once, nor matching jacket and pants sizes simultaneously (i.e. they'd get an XL jacket and a pair of M pants). Most shops got 1 unit (2 max) in each size, and many of these locations never got a complete FSR. In total only a few places ever received the black/red units. Something like 2 stores in Japan, 2 in Canada, 5 or 6 across Europe, and less than 10 in the US.
The primarily red suit came along a little later and while not as popular as the black one, availability in shops seemed even more limited. Certain shops said that Jordan Brand themselves recalled some of the red units due to "quality issues." There are red ones that still pop up on eBay (the black ones almost never do), but some may be these same recalled b-grades.
The other color suits are another story. I don't think any US TZ shop ever carried them. I was in regular direct contact with several shops who expected units but never received any. Nike eventually sold them, but literally got rid of ALL the pants they had within about 2 days.
This whole line turned out to be an inexplicable wasted opportunity. When JB sold "OG flavored" (not quite 1:1 retro) apparel lines alongside the AJ IV and V back in 2012 and 2013 (the IV Archive, IV OG Twist, and V Archive lines, which slowly reintroduced some Nike branding), there had to be at least a few thousand units produced at minimum. They were widely available on all the foot sites and in chain stores as well as Nike locations, and by all indications the styles sold really well. I was under the impression that because the Archive lines were as successful as they were, it likely influenced Jordan to re-explore Nike branding on retros of the first 6 AJ models.
On the contrary, Nike/Jordan didn't even give the 2017 AJ V Vault line a CHANCE to do well. They made and sold a minuscule amount of units and gave the line next to no promotion. I understand the idea of limiting SOME products to build hype, but the "limiting" in this case was on the far end of extreme. Product can't generate hype if the majority of consumers aren't aware of it and *literally* have to scour the ends of the earth to get it. I have yet to see another local person wearing a remastered Vault jacket besides me. A few people have recognized it and asked about it thinking it was a well kept 1990 original at first glance. The only other person I've seen wearing a new one was Drake, and that was in an online pic in one of those Facebook shoe site articles. Hold up, how could I forget, make that 2 people I've seen wearing a new one. There was a Jordan.com article from the release of the AJ V Cements where they interviewed a so-called "vintage clothing expert" from the shop Procell in NY. The guy turned out to be a colorway mixing dweeb (red jacket with blue pants) who wasn't even alive when the suits first dropped in 1990. Some vintage expert, LOL. But seriously, no company is going to build positive hype when basically no one out there has access to the items they want to hype, even if one over-hyped celebrity is wearing them.
I would have called this whole thing a textbook Gentry troll move, but 1) God forbid he ever went with Nike branding on ANYTHING other than his own personal items, and 2) he wasn't yet back with JB. Being that he is now, I'd venture to say we'll never see these suits released in anything close to OG form again. Ever. But I digress.
The handling of the 2017 AJ V Vault apparel makes absolutely NO sense. In the entire history of Jordan apparel, the styles from 1990 associated with the AJ V were arguably THE most popular. I'm talking, EVER. If someone mentions "old school Flight tracksuit," more often than not the style that comes to mind is the AJ V suit. Yeah, a few rappers here and there started wearing the III's and elephant print threads in magazines in '88, and then IV's with some cement splatter and Flight scripted gear in '89. The streets were always quicker to pick up on "cool" styles before the mainstream. But the whole trendy celebrity thing really blew up in '90. Both the apparel and footwear designs from '90 were ahead of their time and at a peak (and still are timeless to this day). They transcended sports function/sports fashion to wind up being seen on numerous celebs throughout the mainstream media, not the least of whom was the one everyone remembers - Will Smith plugging a different tracksuit and fresh AJ's every week on Fresh Prince. That's pretty much the origin of the whole "celeb influencer" concept, only the TV set and magazines played the role that social media plays today. And oh joy, look what it has evolved to, with glad-handing parasites like Khaled and Cardi B who have gaggles of followers, LOL.
On a serious note, nostalgia is a pretty powerful concept/emotion nowadays, especially among GenX/Y'ers, which in turn often rubs off on Millennials when they hear stories that take on near mythic proportions about "how good certain things used to be" in the days of yore. What's old really has become new again. How is this important for a company like Nike? Simple. Nostalgia can potentially be big business for whoever can tap into it correctly. Nostalgia can help the target demographic explode beyond 15-29 or whatever it may be, and bring back previous consumers who aren't happy with (or buying) current products. Jordan probably could have profited significantly with the right amount of promotion and production on these suits, yet instead they turned the line into the absolute smallest of niche releases. The quickest of quickstrikes. A soon to be forgotten afterthought, or what'll be a trivial footnote years from now.
I think they totally screwed up in this instance, and the worst part of all is that for those of us who waited almost 30 years to be able to buy fresh, new versions of these exact suits, there will likely never again be another opportunity.
Anyway, that's it for my rant. I'll probably have more to say about these soon, though. My thoughts in this post never actually address how well I think the remastered models compare to the originals, or the details on the remastered ones that I think the design team got right AND wrong. But there's a good chance I'll get to all that eventually in another post.