I agree on the thin cutoff wheels. I think I can get my hands on some that are 0.040" thick. The B-pillar is just 2 layers, and is a fairly flat shape. Those cuts should be straightforward.
The A-pillar might be a little tricky, still. It's got a funny cross section, and is pretty thick. I'm hoping that the center of the channel will have a usable shape, where I can fit some kind of tubular or sheet metal sleeve.
I hope to have the cuts made and pics taken by Sunday evening. I'm planning to leave the truck's body on the rotisserie, but level it out and lower it down onto 4 jackstands, placed to minimize the bending stress on the whole vehicle. I'm also going to lay out some lines on the pillars, and measure carefully between the lines (A to B pillars), in order to document the initial distance between the lines. When it goes back together, all the dimensions had better be close to the initial ones, or I screwed up somewhere along the way.