Regarding the roof pitch issue, there are some choices you can make, besides stand-up frames on roof or ground:
(1) Install flat on the 15-deg roof part and get good output in summer, not much in winter.
(2) Install on the 75-deg part for good winter performance (if facing south), not much in summer.
(3) Install some of each!
I have a similar roof. My first set of panels (2 x 180W) I installed at 45 degrees tilt on the top roof, using unirac components. It is attached to the standing-seam metal roofing using S-5 clamps. The hardware cost a fair bit, and also I get worried every time the wind blows, even though it's designed for the task, and has withstood all the gusts in 4 years now. (Nothing much above 50 mph here though.)
I got a second pair of panels more recently and decided to mount them flat on the top roof (about 15 deg). They will only work in the summer, but at $1/watt they are worth it anyway, and "real" mounting would cost more than the panels! If I were to start over, I might have put the first pair flat on the steep part of the roof and call them winter panels. The 45-deg ones, too, get partially snow-covered in winter so my winter output is minimal, unless I want to climb onto the roof and shovel the snow off the panels - can't reach them otherwise. This is a backup power system so I'd only do it in case of an extended grid outage. Had they been on the 75-deg roofing, the snow would slide off (and I could reach them with a roof rake).
Separate charge controllers for the two sets of panels, BTW. That's essential if the panels are rather different, or if their mounting is different. Therefore I can see that, this time of year, early in the day (and perhaps late in the day too) the 15-deg ones give more power than the 45-deg ones!