I know that necessity is the mother of invention and many experienced adjusters have their own system for getting a rope over a roof structure to either clip into a work positioning harness or simply use as a hand line.
Here are a couple of videos that demonstrate a couple of very effective tools and techniques:
1) Weighted Tennis Ball w/ Bungee Lanyard (AKA "Comet Ball")Attached to 110 lf Arborist Cord (AKA "Target Line"): Demo of placement over a 46' high ridgecap - http://www.youtube.com/watch?v=pT6aRgwCUIg
Now I know that some of you were thinking "Lucky Shot, wonder how many takes it required him to complete"...Right?...So here we go with another video that demonstrates 5Xs in a row: http://www.youtube.com/watch?v=ZMCJ5gPnesc
Overall a very effective technique that I would choose over most any other line positioning device (inc. Hyperdog slingshot, surf rods, cross bow, & chuck it) in the 2-4 story, open access to ridgecap catagory.
2) The second tool is simply hands down The Best there is, the LL II Line Launcher for 2 - 12 stories, A dummy launcher modified to carry Target Line using Ramset loads to power it up to 120+ ft high: http://www.youtube.com/watch?v=6WbA...WeXY Notice that from deployment to positioned rope is completed in under one minute!!!
Ridge protector can also be placed at the same time as the rope to prevent the all to common rope abrasion mark on the ridgecap: http://www.youtube.com/watch?v=9sWFyRPCOXM
JUST THINK, All this and a hundred more life saving full roof specific rope access techniques with the correct training program.
http://www.youtube.com/watch?v=3iXLAFkwgj8