10 years ago by
A Pianist
Thanks for your question, another tough one to answer in a forum!
My gut instinct is to send you in a completely other direction, and postulate that the real problem in your trill is between 1 & 2, not between 4 & 5. I would take any of those double thirds trills and only practice the lower notes, going through ALL the stuff I write about the thumb in Honing. That should transform that part of your hand so completely that it now looks and feels utterly different from before, and offers such a wonderful, functional support to the outside of your hand that trilling between 4 & 5 ceases to be any problem whatsoever...
Lately I've gone back to a similar problem, the double thirds in the coda of the 4th Ballade, and working this way has given me a new sense of authority in the passage...
AFF