No.4 trigger stoning..and other question

[bow]

I am very cautious about this sort of thing, because there is no going back once you do too much. Altering the angle of the cocking piece can be a big mistake for non-experts like me

I'm a non espert but like you. I used same tecnique i use for sharpening my wood chisels: lie cocking piece surface plane on a 6000 grit honing ston and every 5 " strokes" i reassembled the bolt and checked weight. this way risk of altering thar surface is minimum. Now trigger weight is 2 Kg. and i leave it and reassemble the rifle.
I have also 5 trigger of back up and 5 sears and five cocking piece.... there's room for error.