It may be that you haven't adjusted the pedal spring tension properly. (Oh wait you mentioned that...) Have you lubed the springs in the pedals? You should be able to twist out them pretty quickly. Is this your first experience with clipless pedals/shoes? If it is, it just takes some getting used to. I remember falling at a bike expo at the beginning of RAGBRAI and a guy in a recumbent trike asked me if the pedal were fairly new to me. Yep. He told me you'll fall 3 times before you learn to clip out quickly. I took a lot of comfort in that because that was my 3rd fall. He was right.
I can't answer the compatability question.