As far as RUF goes, I know 1st and 2nd gen springs are about 48" and 3rd gen are are over 50". It will take some trial and error to figure out what combination of springs will work for you, you should be able to mix your pro comp springs in the mix in some way.

I think the 6 shooters with rcv's sounds like a good setup. I know a lot of people hate on TG but I think you'll have a hard time finding many/any failures with the 6 shooters. I also don't think you have to use TG's high steer if you don't want too, Marlin, all pro etc. will work. Is it cheaper to get TG's high steer with the knuckles?