Reducing tension may reduce his ability to control his airplane, or it may improve it. You never know until you try. That's the whole reason why it's ADJUSTABLE! Some like it as tight as possible. Personally, I learned with the factory setting, and so it doesn't bother me. Everyone is different. I suspect that if I flew with Bruce's radio, I'd have a tough time until I reduced the tension some. You never know where the tension is set on his radio. So, reducing it some may actually help. You can't set at your computer and say it will hurt. Just like I can't say it will help. All we can do is give suggestions, and let him try them and see what happens. You're trying to squelch a suggestion that just might help him--you never know.

And, flying with thumbs and forefingers doesn't necessarily give you better control either. I fly with just thumbs, and do quite well, thank you. It can be done either way. I don't tell people you have to use just thumbs, so others shouldn't tell them that they have to use forefingers. Let them learn their own way--whatever feels natural, and in the end, they'll be a better pilot.