Vor'e! Thanks for the feedback, guys!
I tried a mock up of a normal flak vest pattern and it just doesn't sit right with the curves. It wants to bunch up around the chest area, I imagine having a belt and any other waist items sliding around on top would also make it twist if not secured. I think the regulations state that the vest can't show beyond the waist items. Maybe if the pants come up high enough to meet any belts it would work? Or the bottom of the vest could be in the same fabric as the undershirt so it just looks like the undershirt is tucked into pants?
I believe you're right on the note of the vest not being allowed to extend below the waist items. One of the things that might help you with a vest is making sure it doesn't extend below the curve of your waist; the ribcage is rigid, and tends to rotate as a unit, so while there will always be some room for fabric on top of it to "shift" and "twist" - you are far less likely to get any uncomfortable bunching or major shifting if the vest is fitted to the ribcage + making sure it's a snug fit.
If it's not snug, it has that much more room for give to shift around.
As for your other questions, I'm assuming those are in regards to your soft-parts build, rather than mine, right? The bottom "flight suit" is, when your kit is fully assembled with armor, accessories, etc, supposed to look like one solid unit. To my current understanding the flak vest can be a different color (correct me if wrong!) but you can have a two-piece flight suit (ie; pants and shirt) provided it -looks- like it's one piece under that, as Jethro said.
You basically just need to hide the seam of the pants, which in my build, I intend to do with a thick girth belt + Kama + All The Hip Things
I'm also not App Team, but everything looks good to me! I might steal your idea about the thumb holes to stop your sleeves from bunching up, that's genius! And I agree with jethroskull, you can definitely do a padded vest, the only thing you'll want to be careful of is how hot all those layers will start to get, but you said you're a historical costumer so you'll probably be fine
MUH LAYERS. Yep, heat is an issue for me, but between the fabrics I plan on using and the way I'll layer things, I should be able to keep it comfortable both for warmer weather and for cold weather. The hardest part will be having to have my arms fully covered... I usually leave my elbows bare because it provides like, blood-circulation-A/C xD
That's one reason I'm going for the quilted/padded flak vest - I want a fairly thin material for the undershirt, which will make it cooler (and not be great for cold events by itself), and provide the needed protection for the metal armor plates when I inevitably bump into things.
Re: thumb holes: DO EEEET steal away! I -hate- clothes bunching up out of where I want things to be, because it always ends up so uncomfortable even without considering how it looks. It's probably the first thing I think of any time I put an outfit together.
