JUst saw this thread as I was having the same issue. I took the hook off of the clarinet, and at the bottom of the slot section of the thumb hook, I opened up the slot togo over the screw hole, moving it above the bottom slit peg, thus gave me approximately another 1/2 to 3/4 of an inch higher, now works great. By now you are probably Way past this issue., Just trying to help.