Hey, I've been playing for some time now, a year or so. Sadly, I've never learned how to hold my guitar neck properly, especially playing at around 9th fret. Where is the best place to put the thumb, cause I've noticed that it's the most important thing.
Also, how do you play something like this, how far do you roll your finger ?
I think these are things that can best be explained through live demonstration. I also think it is essential to go through that when it comes to posture, hand positioning and all other things that involve your body. For any other aspect of playing it's no problem to teach yourself, do on line lessons or pick up street lore, but take one lesson from a qualified teacher to have yourself instructed how to properly hold the guitar and how to move your shoulders, arm, wrist and hand. This because wrong habits can cause painful and permanent injuries. No really, I'm not kidding. It's that serious. You can be the most dreadful musician and live happy with yourself, but a carpal tunnel syndrome or any other RSI can wreck you for the rest of your life.
See a professional and have the matter cleared up.
my advice would be to find a position that feels comfortable try lots of differnet ones if it hurts or feels uncomfortable do hold it that way