try swapping hands every now and then. if i'm ever trimming like a steep bank that requires a good bit of trimming i use my normal left hand on the trigger and right hand on the handle for a bit and then i change to right hand on the trigger and left hand on the handle for awhile. i guess i'm just used to doing things with both hands. when i worked at an auto plant i started out painting with only my right hand. carpal tunnel symptoms soon set in so i gradually learned how to paint with my left hand as well. you wouldn't believe how much of a difference that makes. i was able to just swap hands over and over throughout the day and that made all the pain go away. anything done the same way over and over is bad for your body. it will gradually breakdown from overuse. the key is to constantly change it up as much as possible. it will feel awkward at first but with practice you will get as good with your left hand as you are with your right hand or vice versa. anything you can do with one hand you can do with the other. it just takes a little time to adjust. before long you can do it with either hand.