Yes, I had the teeth guard, know what you mean about big and awkward/cumbersome.

You might try, before going to bed, eating an apple or bagel. I read somewhere that tooth grinding/clenching is how the brain "twiddles its thumbs" :-) And if you eat something really chewy before bed it will kind of wear those twiddling muscles out? Have you tried chewing gum, etc. during the day? Just keep your mouth working on something so it won't take it out on your teeth.