I play tenor horn as well. My right hand shakes and that makes the sound shake. If I could hold and play with my right hand it would be easier. I also play French horn and that is easier because I can rest it on my knee and my left hand is busy pressing keys so doesn’t shake so much. I was diagnosed two months ago and have been taking Madopar. It may be helping a bit, but we’ll see when practice starts again next week. I’ve been trying to find something to support the tenor horn. I thought of a eupho marching harness but the music shop I asked didn’t think it would work. Any suggestions? Music and bands are such a big part of my life.