For my driving (40/40/20 - pavement & jumps / gravel / hard-pack dirt) I'm planning to use 1M cSt in center, 500K cSt in rear, and 100K cSt in front. I prefer to have the center as close to spooled as I can get, with the rear just a little less so. If I was trying to do anything even remotely competitive I'd go 100K front and rear, and depending on how it handles possibly drop the center to 500K.