If I brace the truss, I'll weld an additional support to the back of the truss tube and have it bolt to a bracket welded to the differental cover. Its a easy and common way to add extra support to the 4 link trusses.
I also don't think I will need it and because of that I may not. The only reason I was considering it is because its really quick and easy to do. Also, since I'd build it all myself it would be cheap as well.
On a different note, getting the 4 link to this point was interesting. Originally, I thought this was a TJ specific 5" Stretch kit. That would allow me to simply follow the Clayton directions, tack weld it all into place, and call it good. Easy day, right? Answer... Wrong. Turns out it was a standard TJ 4 link kit originally. Then, since the guy was back halfing the frame of his YJ during the install he tailored it with Clayton to fit his needs. This all means the lower arms are about 31"-32" long while the TJ 5" stretch arms are 35"-36". I already know what your thinking (ask me how I know), just move the brackets back, right? Answer... kind of. I moved the brackets back, but it takes a whole lot more to set it up and keep all the 4 link angles correct when you move them back. The Clayton frame brackets are specifically designed to match the curve on at TJ's frame to make it easy to set the 4 link angles. When you move them back, you have nothing to referance off since the frame straightens out. Additinally, the centerline of the 3.5" axle tube on the 14 bolt is farther back then a Dana 44, 8.8, or even a Dana 60. Heck, most 14 bolts only have 3.25" tubes. Since mine is out of a cab and chassis truck, the tubes are larger. Anyways, this all means the axle would be back farther then it would be with one of those other axles.
So whats this all mean? You can't just move the brackets back 5" and get a 5" stretch out of it. With my set up, it would have gave me closer to a 8" stretch in doing that (once again, ask me how I know). Anyways, since I was setting it up my own way already, I also set the lower links farther apart to maximize the trangulation of the lower links (not too much though). I then set the frame brackets accordingly to match and still meet up correctly with the angles needed for the 4 link truss.
Once I got all the numbers straight, angles straight, and 4 link numbers right I was then and only then able to set it all up. I spent more time setting it up on paper then I did under the Jeep.