I am trying to shrink some spots the front seat tub on my 29 phaeton with a shrinking disc. It looks like someone or actually many people took pleasure kicking the panel from the back seat. It has several large dented areas on the panel. It appears the panel is shrinking a little on the places where the smaller dents and imperfections are, however there are 3 larger areas (see black circles) that pop in when ever it try to shrink them with the disc. I am pretty sure the metal it stretched a fair amount, as I can push the dents in and out like an oil can. Every time I try to put pressure with the shrinking disc, the panel pops in (concave). I can then pop in out from the inside, but it just pops in again when I start to try to shrink it again. Can someone with disc shrinking experience explain what needs to be done to shrink these 8" or 9" circular stretched areas? I have done a fair amount of rust panel patching and other body work, but I certainly haven't mastered metal shrinking. I wish I knew more about it. I have watched several videos and read a book from Frank T Sargent about metal shrinking, but I still don't have it down. Thanks in advance for any help with this question.
Rusty Nelson