I think object space normalmaps don't use the normals of the lowpoly at all just override them but tanget space works together with the lowpolys normals.
I'm not talking about an optimized lowpoly. I'm talking about not learning jack shit about subdiv polyflow with this method. Are you up to industry level? No. Then why are you aiming for speed rather than quality already? Not trying = not learning. (Besides, if you're really going for smarter not harder, make a lowpoly,…