I used the extract batch file to get PNGs from the ktx2 files. Edited one in particular , in paint.net, changing "US Air Force" to Bush Divers, saved as png. ( the new text was on a 2nd layer....I had already painted over the original text on the primary layer.
Then used ImageToMSFSKTX2.bat very carefully and the log indicated success. I had it output right to the community folder area where this livery sits. This batch file also builds/compiles using the SDK
Upon launching the sim, the lettering has not changed. I realize there will be four ktx2's I need to edit since the text spans over two texture files, and is located on both sides. But I was hoping to at least see that my changes were making it through to the simulator.