To meet the CRL's for approval, you'll need to make a vest to mount your plates to that you'll wear on top of your flight suit. There are various tutorials ont he board for how to make a vest, or you can check out the supply depot if you're interested in buying one. People mount the plates to the vest in various ways -- velcro, bolts, magnets -- I have legacy plates and they're all strapped together and drop over my vest.
Plus is it possible to do a lower body system based in military BDUs(Battle Dress Uniform, the cargo pants looking things) as I have found them incredibly comfortable and durable. The BDU system also brings into question upper body.
2 piece flight suits are allowed, but your top would need to be the same fabric as the pants. Exposed pockets (With the exception of the Boba-style front --not side like bdus-- of upper thigh pocket) are NOT allowed, so they would either need to be removed, or covered with armor.
