Cool. I also have a bunch of the vid tutorials I used to cobbled together my workflow bookmarked so if you really need them I can provide. However they are pretty scattered and there is a heavy dose of my own workflow tweaks that needed to happen to force the issue.
Installing Reaper is pretty quick/easy. Getting it setup and designating folder locations can be a bit wacky though. I actually had to create some custom key bindings for certain things too but IIRC not anything that REALLY affects this particular workflow.
And yes... when multi track comping like this in Sonar it's very advisable to group the way I descirbed. If you had been tracking into Sonar with some of the fancy Grouping options available (auto grouping tracks recorded at the same time) then that type of thing is automade from the start however after the fact you have to manually group.
This could maybe be part of the problem (as in if you have each take in their own track and trying to group across a hundred tracks instead of using Lanes).
Cheers.