#12

I Installed the PSI Block onto the ring temporarily by clamping the PSI Block in place. I drilled a 9/64" hole through the dome ring and into the PSI Base. I also used a countersink bit to countersink into the ring. Then I screwed the whole thing in place using the tapered head screws.

NOTE: At this point any lens being used needs to be in place, between the diffuser and the dome opening, before drilling and mounting the PSI Block to the bottom ring.