For the street a 1" sway bar is great in the rear. For offroad a 3/4" or smaller is works best in my experience. A properly setup long arm will flex more than a stock style sway bar can flex.
The addco helped enormously on the interstate with swaying. I just disconnect it when I go offroad. I have heard some people ripped the sway bar mounts out by leaving the addco hooked up when offloading because it's so stiff.
The one inch addco is just too stiff, go with the 7/8, i am running a 6 inch long arm on my wj, with about 600 lbs of overland gear, lots of off camber rock crawling in colorado the 7/8 inspires confidence on and off the trail