Do not adjust your t-bars when the weight is on them. The block that the adjustment screw is in will walk on you, and it will be hard to finish the job. You don't actually need to put it on stands, just throw the jack under the crossmember, jack it up, adjust, and lower. I've adjusted the t-bars on my Ranger and my old Exploder, and each time, it was pretty much a matter of measuring to the wheel opening when I started, then repeatedly raising, adjusting, lowering, jumping on it, and re-measuring as necessary until you have it where you want it.
The very first time I adjusted t-bars, I was lowering my 97 Exploder (the rear springs were sagging, and I wanted it level). I didn't jack it, and the passenger side block twisted so that the screw was almost in contact with the case, and it was a project to get it straightened out again.