Now time for cutting. Make sure you have your dimensions and reference lines scribed in the paint. I recommend you actually scribe the lines so they don't get wiped off.
Also level the Jeep. I did this with a 4' level on top of the hood hinges and a 8' level across the top of rear tub, my hard top was removed. I leveled the jeep just releasing or adding air to the tires.
At top of B pillar is bolt on the outside, now on the inside there is a bracket welded. You need to cut between these two spots.
Now cut the bottom, I used a 6" cut off wheel on a grinder. NOTE: there is foam in the B pillar, it will BURN. It smokes a lot so you will know if it catches fire. Have a water hose handy and start blasting water through the cut if it catches fire. You will have some smoke, but any excessive smoke that continues is a fire. There is a pipe that runs the full height of the pillar, but its not connected to anything below the cut line. The outside skin is a single sheet metal, the inside is double so you need to cut through both, but you don't need too cut through the pipe. On the inside front corner of your cut will also be a spot weld that welds the outside skin to the two inside skins, cut/drill it out as required. Once you think you have the bottom cut out remove the top inside bolt from the B pillar. Now pull the top of pillar out and lift up, if it doesn't come out see where you still have metal connected at the bottom.