Sounds like my guess was pretty accurate. I know these trucks are a touch over 3k lbs stock, I figure most people add to that a bit, even with all the body panels that get cut off. 11" was also just a guess, based on the stock 2WD trucks having a 10" rotor and being about 2700 lbs.
Line size I figured 3/16", you can get away with 1/4" as well and the only thing it will change is how much travel the pedal has.
If you figure out the clutch thing let me know. I usually just get 5/8" for those with a stock Toyota slave, but I am also familiar with 2WD only in this setup. I believe the stock clutch master is 15.6mm or something like that, which is relatively close to 5/8". But again, I have 2WD numbers in my head.