Why are your bands, manifold, and backplate 14lb negative? Crossbar and Bands should be in the ~4lb neighborhood. If you're actually 14lb overweight, you might consider finding an AL or even plastic backplate. Drysuit or double AL80s are still your answer though.I was considering moving to sidemount because I dive double steels in a wetsuit which means I couldn't swim up my rig with a BC failure. With sidemount I could make myself around 14 pounds less negative (no bands, manifold, backplate) which would really help with getting closer to being "balanced". Lots of folks now coming out of the woodworks to say sidemount is more finicky than back doubles for some reason. Weird.
I don't think it's woodworks. Sidemount is far more finnicky than backmount, especially if you/instructor/mentor don't know what they're doing.