Well a used MEC 600JR in 12ga is not that expensive and you could use it to load your spreaders.

just get a bigger shot tube it works fine, like steel shot press has. I just reamed out my shot tube on my press with a reamer to the size a couple .000 bigger of the "X' in the wad. That works great and no change on how you load spreaders or normal shells.
scott

Pay attention now. Here is the straight poop. The PC Post wads, the best spreader on the market, easy to make "more spready" by use of a fuel line addition to the Post, are problem free in a PW 800 B. You just substitute the PC Post was for the normal wad and continue to load shells. No fuss, no muss.