For # 1, on the 6XA(s) - for your model, after flying and trimming it out, go into the trim memory, activate the set (I believe by hitting the + and - at the same time, then exit config. You should now be able to set the trim levers to neutral and the model should be trimmed properly. It wasn't clear from the question if you were trying to fly multiple airplanes from one model config. If so, each airplane really needs it's own model to set up properly, or the trims will be off on all but one of your planes. The idea is to be able to keep the trims on the tx neutral while switching models so you don't have to mark or remember the exact settings. Works great for me, just wish I had a function to re-trim for temp changes. I was surprised how much difference it can make this weekend (approx 15F) when I flew a plane I hadn't flown since summer (85F).
Oh well, hope this helps
JS