I'm learning a blues piece (A-minor pentatonic / blues scale) - the standard shape but in the high-fret position (up at fret 17 and above). I have problems with flexibility when I play in the high-fret region (fret 17 and above). I try to stick to the one finger covering one fret rule - but my hand often ends up in a contorted shape and this impacts on my ability to play smooth when i am trying to play fast and doing lots of bends etc. I've gotten better - but still pretty crap. I often call myself "Tommy Dickfingers" and that should give you an idea of the mechanics of my hand

Now, if I hop into Clapton mode and only use three fingers i do much better - so I am at a crossroads of (i) continue practising the superior technique and use all fingers and just stick it out or (ii) just use three fingers and the third finger to cover both the last two high frets and crack on as its easier and more enjoyable at the moment. I'm not looking for technical excellence - just wanting to avoid getting into a habit I might regret later.
Any tips on playing in high neck positions? Generic hand position? I also play sitting down most of the time - swapping the leg the guitar sits on can help a little bit but its as if my hand shape restricts my finger movement when i try to do it properly.
It could just be a flexibility thing and it may well pass.....bet hey....
PS - I've only been playing a few years, dont get to practice everyday (I'm 40 years old - have demanding job) - so I am never going to be a shredder. I nearly always have my thumb over the top of the neck and do not play in a very "technically correct" manner - but then few do.
Am I just getting bogged down here in a tangent and should I just play what comes natural (which would be the technically inferior approach)?