I never have any difficulty with the block neck joint. For one I do have big hands, but I learned how to play on a classical guitar(neck joins the body at the 12th fret) so I had to learn not to rely on my thumb being glued to the back of the neck. Also when I was younger I entertained the thought of "what would happen if I lost my thumb?" So I practiced occaisionally playing without my thumb on the back of the neck, soloing, chords, tapping, etc. So block heel neck joint has never been an problem for me.