well first of all i hate to burst anybodys bubble, but none of the releases you mentioned are actually a "back tension" i would reccomened a TRU ball BT gold it is a very smoothe back tension and isnt to pricey either, also if your willing to spend the extra money they have the ultra II series with a safety, if you want to learn to shoot back tension do it on a true back tension not a thumb release, if you have any other questions i will be glad to help