Are ladders not an option for safety reasons, confidence reasons or limitations of the slope of the roof?
If the latter, you can make an inverted "V" out of 2x12 planks and lay that over the ridge so as to make an attachment point for triangular 'boxes' you make to form a level platform on either side of the ridge. On those, you place ladders on either side of the ridge, using ladder jacks you then place a board horizontally and you have a working platform to paint the entire peak. Mind you, this is not necessarilly for the timid, but I can tell you from experience that it works quite well.
You can move the triangular pieces to lower areas as you go to support smaller or even step ladders, or as a seat/working platform down at the bottom of the slope.
For the bottom pic, I think all you would need is two ladders with ladder jacks and the platform
Edited to add: Otherwise, you could make leveling pieces and use pipe staging on either roof, but it would be just as time consuming and a lot of heavy lifting getting the pipe staging up, and then setup while on a slope....
Edited again to add: As another option, you could again build leveling bases and put up pump jacks. That would allow you to put a 20'-24' platform up to do all of the painting very easilly. That would be VERY heavy and time consuming but would be easy working. I can't guess at the rental cost of either pipe staging or pump jacks....
I ought to study the pics well enough the first time