I had the same issue with a thrifty and an economy. I moved the buckles on the econ. and put some extra velcro on the thrifty. I just didn't feel like sending them back. I figured what the heck, I'll experiment. My wife is a seamstress and she can bail me out if I mess up too badly. It worked pretty well and If I get fat (OK fatter) I'm all set.
Bob