I love a William tutorial. Too stuff

I have a similar experience with my new nemesis chord A7. It's slightly different in that it seems to be a fairly obscure chord. I've only seen it once. However, it is difficult for me to play without a bum note in there somewhere, so for that chord only I have to tilt the guitar up in order to play the chord cleanly. While William has expertly covered hand/thumb position, it might also be worthwhile experimenting with repositioning the instrument.

Maybe not, but perhaps something to have in your arsenal of possible fixes.