Ake - my advice... don't get too strung up on the 'mechanics' of guitar playing technique...
More importantly, keep your thoughts full of music, live with a musical soundtrack constantly in your head...

Obviously health and safety dictates you should stay a bit more focused on the immediate job when high up on a roof...

But otherwise keep your thoughts musical..

Then when you pick up a guitar you are primed and inspired for naturally feeling what you want to play...
you can just get into it and enjoy having a go - mistakes and all...

Frustration at not hitting tehnique targets can eventually lead to a kind of mental paralysis that stops folk
wanting to pick up a guitar ever again...

This is no new age Jedi feel the force bollox.. it does help...

For the last few days my head has been full of reggae bass lines,
which actually influences my present demeanour, even how I walk arond the house...
Last night I had a really good enjoyable half hour random work out on an unplugged semi-acoustic guitar..

Btw.. too many unmusical people think they can learn an instrument just by copying technique by rote...

They are usually dull to listen to, and a bore to play with...