Thanks to all for remarks, very helpful. Yesterday, by coincidence, I dragged it all out, started building cables and started listening to this stuff after 18 months in storage, starting with the Quart One's (yes, should have said MB Quart). The room is still uncarpeted, so very live, but I put big tube traps in the corners with absorbtive side out to tame it a bit, which it did. The Quarts work fine and sound very good for what they are, despite age. Ditto SMG's.( no buzzing, wire delam etc).
Given room size and layout It was immediately obvious that there's no room on the sides for the SMG's, or any planar for that matter. The next experiment will be to listen to the SMG's and Quarts together as fronts and sides respectively. That's backwards, but until carpet is in I can't setup the MGIIIa's. In any case it may be instructive on how well the planars and box speakers play together. I'll also compare LS50's to the Quarts. These need to be removed from a small office system, a minor PITA. Anyway, I may learn something and establish a good starting point for more experimentation. As for other choices, sorry, not yet. I'm not going for best imaginable solutions while I've probably got perfectly fine stuff on the shelf. "Pretty good" is good enough, at least for now. But there may be a further opportunity when I get going on the height speakers. To be continued..... Thanks and cheers,