Neither. Wind and magnetic trainers are both crap. Get a trainer with a fluid resistance unit and a flywheel.

Yes to using a climbing block.

Which gear you run should make no difference. Select whicever gear will get you to the correct HR zone.

Trainer frame should be completely motionless. If yours isn't you should stop using it.

You should be able to ride your go-fast bike on the trainer. (Just use a junk skewer on the rear wheel, lest you beat up the nice skewer.) That said, I personally use my old bike on the trainer, and also to drive out of town for training. Go-fast bike is too valuable to risk damaging.