I too have to trim a lot of calls.
I tried a Cane Creek C.C. Smoker this year and it is very similar to the XT Havoc in size and sound, but it is made out of a very supple tape. I did not need to trim that one. It seems with the C.C. though after being in my mouth for hours it gets slippery and wants to jump forward if I try to get some volume.
Another call I really liked this year was the Dave Hollran Natural Born Killer. I ruined the first one cutting it too short, but was more cafefull on the second one.