I just went through the past few pages of the thread, so lets see if I can help out with my two cents here:
1) You will WANT at least two Heim-type joints to use where you mount the arms to the truck. You can use bushings, but I think even with 'mild' wheeling, you will be unhappy with the performance of the system. That's not to mention you'll probably wind up eating bushings on a regular basis at that end of the system (even if you only run mild trails). Do what you can to get some proper joints in that location, the rest of the system (axle end) you can use bushings without a problem.
2) I've seen alot of the clayton stuff first hand, and it works just fine. 1/4" wall square tube will work if that's what you have access too. Round is better, but I wouldn't be scared of square so to speak.
3) How much lift (if any) are you shooting for? If you're keeping the lift under 4 ish inches, a 35" arm should work just fine for ya with the things you want to do.
4) While its nice to have, adjustable arms aren't mandatory. It does make setting everything up that much easier though.
5) Shoot for 5-6° caster in the front end (Top ball joints leaning toward the firewall). This tends to be the happy spot, and if you're not running stuipd lift, you shouldn't have to worry about the pinion angle either as it'll be close enough (stock caster spec on the Dana 30s is 4-8° from Jeep).
6) What are you going to do about a track bar (Panhard)? For what its worth, I've never liked the feeling of track bars with bushings in them. I like systems that have heims instead (or similar type joints). It makes the system feel tighter/crisper. But I realize that this a mostly a personal preferance.
7) Granted I'm running an entirely different front end setup, but I don't have any 'sketchy' moments running down the highway at 70-80 mph, though it does take me a long time to get up to that speed.
I hope some of my ramblings help!