Let me guess you need to repair the area where the A piller meets the roof sheet metal,.. Once I get to that point in the Comanche I will see if that part needs to be repaired or replaced and do a quick write up in it. Depending on where the rot is and how much metal I have available to weld to determines how I make a patch panel. If I have the room I bevel the existing metal to make an overlay like I did on the cab corners of the MJ project if I don't have the extra metal to play with I may cut the patch slightly bigger and add a Foch more heat on the welder so when the new patch fuses I have a bit more steel to add to the weld when it melts in. I will try and show you on the MJ as I continue the rebuild on the beast.