I used a See D's stamping mat (it's purple) under the paper when using some small clear stamps, and it helped. I have some funky foam (cheap in Tesco's) to put under bigger stamps as it works out cheaper than buying a bigger mat. I've never thought of mounting clear stamps on ezmount - wouldn't it make them harder to clean, since they recommend washing them in warm soapy water as some stamp cleaners can damage clear stamps making them sticky.
Jan