I didnt really know how to title this entry. I have two students who are brothers. Incidently, they both are double jointed in their thumbs and when they play they play back on the "ball" of the thumb joint instead of the pad/tip. They also buckle their first knuckle on their fingers. This is only on their left hand. I've FINALLY cleaned up the right hand. They both have large hands and no troubles that way. However, its not hurting them and I cant seem to fix it. They are extremely uncomfortable when I fix it. Should I just let them go? Their intonation is better than 90% of my students.