Used to have the solid but needed to drop wt in bm rig. Divin wet so didnt really need the xtra wt anyway. Still juz as stiff as solid but only 2lb. Have 2 bm dbl. 2 sm.1 bm sing. All identical other then tank mounting. Just have to swap my leg pouches and good to go. Muscle mem same nomatter what i dive.
As an instructor tho do you feel it would be better to learn bp w upfront? My experience is that most divers that stick with it end up going bm or bp w eventually.