4/12 pitch on my garage roof I just built. Wasnt bad to work on, but wouldnt want to be up there when its wet, or dew on in the morning.
Anything more than 4/12....would suck. My old shop I went 6/12. Was able to put all the sheets up without actually getting on them, Just reaching across their 3' width while resting comfortably on the truss/purlins.
when it came to the end sheet, I tied off at the ridge with a rope. After all the sheets were on, the only thing left was the ridge, which wasnt bad just walking down the peak as long as a shoe was on a screw head and you kept 1 foot on either side of the ridge.
Never went back up on that roof. But if I had to, at 6/12 I would have done something to prevent sliding off