40 psi not the answer. Put the stock wheels and tires back on if you have them, and drive it. I would bet most of your 'wandering' goes away. Drivability is always pretty lousy with big tires. Nothing much you can do. If you want lifted Jeep with big tires you deal with it. All these stupid threads on every Jeep forum is ridiculous. You are dealing with solid axle rig. My front end is all aftermarket, torqued properly and no worn parts. However with 37's at about 51-58mph I always have 'wondering' or wobble, whatever you want to call it. When I put on stock rims and 33's it all goes away. It is the fucking tires. I drove 2000 miles to Utah and 2000 miles back doing 90mph. No wobble or shimmy. Of course it 'wonders' its a fucking solid axle Wrangler. Deal with it. Every tire at a certain frequency gives you something...noise, wobble whatever.
Not picking on you, just commenting on all these posts on this beat to death topic.