The hi-steer is $$$ but boy, is it ever worth it. My Exploder went from stock to lifted with dropped pitman arm to super-runner steering, to SAS with hi-steer. I skipped the SAS without the hi-steer because I knew it would be an issue (based on my past experience with early J**Ps).
I do not run a track bar because I don't believe in them with leaf springs. Jeep never thought of the issue until the Wrangler due to the added stress of the public request for a more stable Jeep. Obviously a track bar is required on coil spring suspensions. I'm sure there is a case where one would need a trac bar. You just may be it.
I don't have any wondering in the front end. I do have 5" shackles but they are the dog leg style for my axle flex. The front drives straight and true, much better than a stock or lifted Exploder. I believe my Caster is set about 6.5*, but I'm not 100% positive. I haven't installed a sway bar yet but it's in the works. Been too damned cold up here. I am also running RS9012 shocks. I can tell you that makes a world of difference. I run the shocks firmer on the street and soft on the trail. I do crank them up an extra notch when running the freeway or hauling a load or a trailer. I don't have any wobble or vibration, but then again, I'm running a 17" wheel so there's quite a bit of difference there.
You might want to try a sway bar. That might help along with your caster and shackles. I hope it works out for you. That's what I like about leaf springs is that it's a good combination of streetability and flex off-road.
I see you're in Ocean Springs. I remember that stomping ground well. I used to be stationed @ Keesler. I had a great time on the Gulf coast. I had a Blue two door Sport running 33s until I PCSd out of there in Sept, 2001.