I don't know the offroad parks in the Houston area, but I'll make a general comment. In general, 33" tires seems like a good compromise for clearance, offroad performance and street use. And 33s seem to be okay with the stock steering, brakes, etc. The larger tires will also help your departure angle, which may be an issue in a ZJ. You may need to regear for 33s.
You can have a blast on 31s. It all depends on what you want to do. I've got a Wrangler, but I've wheeled it on 30s, 31s, 32s and 35s. There will always be obstacles that you cannot do unless you go to up 35s, 37s or 40s.
You are smart to be figuring this out at the beginning of your build. It's cheaper to just do it once.
My Ammo Can Console: http://www.jeepforum.com/forum/f12/yet-another-ammo-can-project-finished-1498520/
My 8.8 Swap: http://www.jeepforum.com/forum/f12/yet-another-ford-8-8-swap-extras-1565339/