I would suggest starting with the flightsuit and working out as it will be hard to fit a vest without knowing how the stuff under it fits.
This is what I'm doing.
I'm trying to build from the inside out so I have to get my boots, flightsuit, gloves (got these), then vest, then belt and Kama, and THEN armor plates... only problem is I can't seem to find a flightsuit in my size and color
Having a flightsuit on will help with measuring your vest and making sure it fits over top of the flightsuit, and having a vest will help when you mold your plates.
Do you have a WIP thread Kad?
Keep it up!