I do not own any optical sights for handguns so I can't tell you how good or bad they are. I do believe that Amazon sells them though. You might start there.
Holosun used to include a picatinny mount with the 507c but now sell it separately (I believe). Since the Comp is the same footprint, you should be able to use the same picatinny adapter to mount it on a PC M41.