RE: Aircraft rolls with up elevator
The up/down trim is like everything else, it's subject to your interpretation. That's where you develop your "experience".
The up/down thrust test has you interpret the loss of thrust. Whatever the airplane does almost immediately after losing the thrust can be what you're looking for. However, if you don't have a balanced CG already established in the airplane, the test result is going to be clouded by the airplane's trim change, and the trim is going to be biased by the CG location.
So sort out your CG and then do the up/down thrust test.
BTW, the way I got my Ultra Sticks to snap halfway decent was after moving the CG back and being less than satisfied with that, I increased the elevator throw. The elevator has to have the strength to stall the wing. Moving the CG back increases the elevator's efficiency/strength. But if just moving the CG doesn't help enough, then simply rig the elevator to get that strength. Sticks are lightly loaded. Lightly loaded airplanes are less easy to stall. The horizontal tails on sticks are very low aspect ratio. Stubby tails are less efficient, less powerful. They not only look square and fat, but they act the way they look.