Update on the “thick” seat post…

Too much time later and I now have an empty seat tube. Too much seat post inserted to be able to cut all the way with a sawzall (over 12” of post inside the frame) left me a bit stuck as I couldn’t piece it out, nor could I use a slide hammer… or so I thought. Used the 5/8”x8” bolt, a washer, 2 vice grips and a 10lb weight to make my own shitty version of a slide hammer. An hour of pounding, pulling, reinserting the bolt and redoing the vice grips later, I now have an empty seat tube waiting for a good cleaning.
Hope nobody ever needs to use my method but if it eventually helps someone else out that’s too stubborn to throw out a good frame, then I hope it works better for you!