Well the problem with the PKM conversion is there isn't much room in there for a striker setup anyway. A few years back when I was really trying to get this working I toyed with the idea of the "striker plate" which I learned was already done on the Swiss Pe57 (I think)? It is in one of my PKM discussions.
The other thought as I mentioned is to notch the bottom of a bolt carrier and use a different spring (perhaps AK spring) that is secured to the back via a vertical post that would clear the notch. Presto you made a short-spring PKM with room for the trigger group.
Only other thing I can figure is to use a dual-spring setup that is thinner than the standard, and is on both sides of the carrier. Allows clearance for a standard AK-style trigger group. The problem with THAT is that in my testing I couldn't find a good spring that would work well on both sides. IMO this is the best approach because it is the least labor-intensive, but locating the proper springs that work to operate the action is going to be the trick. Perhaps VZ-58 striker springs. Something of that diameter.
I got far enough to press the bulge in the bottom of my receiver shell but got distracted by Real Life and put it on the back burner. I would like to get cracking on it once again!