Nice mount! I didn't come across this post until after I bought my CMA-345 and RPA-U mount hardware. Question though, I noticed you mounted your pipe flang to what looks like a piece of MDF board which is in turn mounted to the ceiling. What thickness and what type of wood did you use for the board you mounted to the ceiling and what bolts did you use to mount the board to the studs in the ceiling?
I've bought myself a 3/4" MDF board 2 x 4 feet in length, just need to cut it down to size and bolt it up to the ceiling similar to what you've done. Curious if that's what you used or if you went with real wood, it's hard to tell from the pictures...