True flight did a test a few years ago and found 8 degrees of heli was a good compromise for spin and speed. I always recomend depending on your style of rest to get as close to that as possible. I have seen a lot of people dab the leading edge of their fletch with a dab of glue in order to help them hold up through a biscuit. Other than that, I dont know what else to tell you to try. Once a biscuit gets worn in the problem usually goes a way. Just try to tune so your fletch goes through the same way on the biscuit everytime. That will help for even wear. Four degrees should always stabilize better than one. One degree might work out to twenty or twenty five yds., if your tuned to absolute perfection and have great form,and use 1 1/8 cut heads or smaller, or mechs. You would just have to group tune and find out. Four would be a better all around compromise. Just my thoughts, and hope it helps.