About to order parts for bag setup, what do I really need?

[ElkyRacer]

I just ordered a pair of RE7s and RE8s from a ebay member today, which will ship wednesday. Im looking to order my front plates from Suicide Doors, as well as my triangulated 4 link parts. The build is going to be a 64 Long Fleet that will have a Z up front to lay frame on a 29in tire, a 5.3/4L80E/Ford 9in. The truck will put out around 450hp(turbocharged) to the wheels, see some track duty(hard launches with slicks) and be used occasionally to tow a car trailer/Jeep.

Now onto the questions. What size tubing should I go with for my application? The lowers I was planning on square tubing, mounting the bags about half way on the tubes, with rubber bushings at both ends. Uppers will be adjustable with bushings as well. SD sells the bushings with both 3/4 studs and huge 1 1/8 studs. Both the same price, but Im thinking tubing will run more if I go with the 1 1/8. Is this needed? Will 3/4 be fine? Is bigger always better?

For now just to get the frame rolling Im just concentrating on those parts, not any valves/tanks/compressors as Ill have more need for drivetrain parts. What else am I missing?

Kyle