Pookie, I went ahead and started a BIY PKM thread as well, but it's over on TheAkforum.com. I have been redesigning the firing pin striker mechanism. It's been keeping me busy. I had to scrap the idea of the tension spring trolley. There was no way to attach the tension springs forward of the bolt because of interference with the bolt.
I looked the PK receiver and carrier and screwed around with my idea. It would work but it's not something I'm crazy about. Too much fabrication and lots of small precisely made parts. On the other hand, I thought about your idea and the information you posted and went over the receiver and carrier fit for about an hour. I think your idea is the better one. Provided hammer can hit the "L" shaped transfer strut hard enough to set off the primer. I think I can modify an AK hammer to work ( if it wasn't so damn hot and humid in the garage I would be out there right now). You could keep the spur on the bottom of a full-auto AK hammer and that could interface with a modified PKM trigger group. I can see the whole thing in my head, out of battery firing could easily be prevented.