Hang on a second, I thought the bike looked a bit familiar - I've been reading up on as much as I can about making a mount for an eyelet shock, yours is holding up ok I take it?
The shock mount is holding up great and no sign of lateral flex in the setup. I do have to check the shock bolts before each ride though as they do seem to like to work loose just enough for a little play to be in the system. Probably time for me to use some locktite.
I bit different to the PF but when I swapped my coilover shock on my Marin to an air shock, I'd initially set my rebound a bit to rapid so was getting a bit of a ping when it fully extended too quickly, maybe try softening the rebound a bit and see if that helps
I'm pretty sure that the clunk is in the shock. I've pretty much decided though that I am going to either get a new shock like an RP23 or send the current one away to be tuned specifically for the frame.