I recommend not using one. Get an adjustable front track bar to keep the steering parallel with the track bar and you will not have bumpsteer. A drop pitman arm is not needed at 4" lift.
The adjustable trac bar won't work with a leaf sprung jeep. also a stock XJ pitman arm drops more than a yj/tj one and can be found in junk yards for $5
If you're going into the pitman arm anyway you might consider all or part of what I had installed;
Since I'd seen over the years many posts about weak links in steering, when the gearbox started leaking I learned of a stellar shop locally and even though I brought these parts from outside, they had no problem intalling 'em. Despite "Betty" being an old '78, she drives like a sedan, straight and true on hard surfaces.
I believe the OP was inquiring about a TJ, and we've had some good replies about YJ's and XJ's. I still think stock steering is fine at 4" with an adj track bar.
Later model Jeeps don't need the beefy bracket you picked, Jeep did away with the flimsy 2-piece CJ steering box bracket in '87. The flat pitman arm really only works in high-steer applications. I used a SJ pitman arm when I needed a flat arm in my YJ with highsteer.