Most bride seats are ADR approved, some are even FIAT approved. Ask for the ADR approval paperwork when ordering.
This is only my thoughts, but think about how the seat will react in a crash. As I would like to have something that will not buckle and causing trauma injuries just so that I can have the look of the real thing. Skimping on some things when building your car will not be a problem, however do not compromise your safety for the sake of looks.