An adjustable length trackbar eliminates the need to drill a new mounting bolt hole in the passenger-side track bar mount. Drilling a hole to move the front track bar over is only done as a band-aid fix when a non-adjustable track bar is being used. So if you're installing an adjustable length track bar, don't drill that hole.
Once the taller springs are installed, adjust the track bar length this way. With the Jeep sitting on the ground, assist the Jeep so it can self-center itself over the new springs by standing on the front bumper and using your body weight to move the Jeep up & down. The Jeep should be well centered after that. Bolt the driver's side of the track bar in place, then adjust the track bar's length so its passenger side mounting bolt hole is matches its mounting bracket's bolt hole. Install the passenger side and you're done.
Whether or not you need a dropped Pitman arm depends on what track bar you're installing. If you're installing the RE1610 that bolts to the factory driver's side track bar mount the OE factory Pitman arm is what should be used. Of RE's two different front track bars, this is the only one I'd use.
If you're installing the RE1610 track bar, which I had and don't recommend, that requires the RE1611 dropped track bar mount which requires a dropped Pitman arm.