As the befuddled thread-starter, may I thank every-one who has contributed ?

"It depends..." was the result I'd feared, but that's life...

I download lots of eg MMD and Richard Mandel / DE free OBJ scenes+sets. Mega-poly-counts and import-scaling issues aside, each often has mildly conflicting heights for its seating, door-ways, stairs, ceilings and props. Add a Poser character who may stand anywhere from 5'6" to 6'6" and, V4 or LaF, the scene looks wrong, wrong, wrong. Sometimes iterating entire scene scale by a few percent will suffice. Sometimes XYZ scales need individual treatment. My DA render notes usually include wary proviso, 'Scaled by eye'...

I've acquired 'Balancer' which can 'intelligently' simplify mega-poly meshes. After years of struggling with a CAD program that only supported 'coloured' rather than 'textured' OBJs, and is worse than PP_11 with FBX, I think I've found a replacement. Also, now that P_12 seems to have settled as a stable release, that's on the buy-list, too...

Again, my thanks. N

ps: I'm still hoping P_12.n will add full 'Make Human' FBX rig compatibility....