Here is the solution for the track bar issue.
Best thing to do is unbolt the track bar and the truck will center itself, then mark and drill your holes. When I disconnected the track bar from the axle the truck seemed to naturally find true center. Not sure how, but it did. Could be shocks, springs or end links pulling it back to center. Then you can raise the track bar back into place and see where the new holes need to be drilled. I went a little too far to the left (because I didn't do the above method) and it pushed the axle too far to the drivers side, basically giving me the same problem, just on the opposite side. I ended up slotting my hole to the right side of the truck to push it back to the right and its perfect now. You will have to remove the passenger side exhaust pipe to have room to drill.
I used a 5/8 bit for mine. It's a tiny bit bigger than the stock hole (9/16 would probably be perfect) but once you tighten everything down it won't matter. Mine hasn't moved at all, even though I have a 1" wide slot. Be sure to triple check everything before drilling holes. Start with an 1/8 (or similar) bit through the mount towards the rear of the truck, then slide the bolt back in the stock hole and use that as a reference to get the 2nd hole marked. You want the 2 holes to be as close to perfect as possible to prevent binding. Once you have both 1/8" holes drilled, drill out the 5/8 hole. It's really not as bad as it sounds once you get started.
First pic is the original hole I drilled, 2nd is everything bolted up. Notched about 1/2 the width from the 1st pic.