Advice Needed - Wing

Been diving up to now with a BCD + 12L or 15L with 3L Pony but need 2nd set
of gear. Having briefly used a wing and twinset (only in the pool) and
found it very comfortable, have decided to go that route..

I've been offered a second hand setup with twin 7L 300's banded with SDS
quick release, MDE manifold, Custom Dive valve protector and Dive Rite Rec
Wings Transpac 11.

Doing a Google, it appears the Rec Wing comes in 2 versions with either a
backplate or the version this is, with a stiff pad. The SDS quick release
is bolted through this pad and seems to flex from side to side a bit. Any
ideas? Should this release system only be used with a backplate? Can a
backplate be added to the existing harness or not?

Graham.