Problem with rockwells is uptravel. I narrowed the set I have, ran two short side inner shafts. But the 3rd is huge, thats the problem I was having with them in my old buggy build.
I ended up using a pair of steering 60's and ditched the rockwells. Problem I was having is how to set up a proper 4 link with 32* steering front and rear.
Are you getting two steering axle's? If not the stock steering raduis is week, the most you can push them is around 32-34* max, a stock 60 can do 38*, and thts before you clearance the U-joints, after that the 60 can easyly do 43-46*.
Leaf springs and rockwells produce alot of axle wrap due to the 6.72 gearing, even in the front so build bolth axle's with anti wrap bars or you will twist your springs.
Be prepared to build a taller jeep than your used to, what i mean is the massive chunks force you to go up so that you can get some up travel.
Pinion brake's, I used a Toyota rotor with a Toy caliper. I never got to run them but this is what I was told to work the best.
I hope you don't get frustrted with them like I did, they are alot of work to make happen in any Jeep/buggy. But with anything time will tell along with money.
I found it cheaper in the end to build with two steering 60's. Once you put a good set of shafts in the 60 they will last just as long as the rock shafts.
Oh what year are your axle's? This will help figure out what style shafts you have. I had one 68 and one 62, the early one had the Bendex axle joints and the 68 had U-joints style. I had to buy U-joint style one's for the older and then differnet seal plates to match.