I can relate to the signature problem. I had some difficulty with TTB, a while ago, when getting a new pass book, because my signature had changed. In my case I have quite serious arthritis and I find it tricky to even hold a pen, let alone make reproducible signatures. Hilariously, they let me continue trying until I managed to get a match with the signature that they had on file that they were satisfied with.
Somewhere on your pass book there will be an image of your signature that is only visible under UV light. A 'black light' pen will reveal it - and you can then practice until you can reproduce it satisfactorily.