Roof pitch track is what you need, and what Kezorm stated is pretty good information. For most basic roof pitches, you can modify what is there. In theory, you could add a tiny bit of high lift it looks like from the pics, but frankly that would add un-needed complication. You might need to change your cable length slightly depending on the exact geometry you end up with (more roof pitch will cause the center line of shaft to need to move up to clear the top section past the drums in many cases). Springs will definitely need changed. Sometimes you can get away with using a trolley opener if you remount it, but most people will change that out as well. If you aren't afraid to get your hands dirty, this is a doable job onsite.
John
By the way, yes once you get over 12:12 pitch you want to go to vertical lift drums.