In reply to Aaron75:
No guidebooks describing what you're after. Best you can do is use the regular NTK Jotunheimen guide with summer descriptions and interpret that how you will. Peakbook is probably going to be your best online resource. Most people (and that's very few) usually do mixed stuff in Jotenheimen during late autumn while there is less snow. That's going to be closer to Scottish style mixed. You're probably going to be swimming in snow during winter and early spring, but I presume you know that.