As others have pointed out the accuracy and precision of the FX gauges are not ideal, so I ordered a Sekhmet. I the meantime I pulled the gun apart cleaning and lubricating as appropriate. Also, my 2nd reg had 12 Belleville washers installed. I wondered if that was why I had no low end on that reg, barely cracked read 95 bar. So, I only installed 11 spring washers. Upon reassembly I think that may have been the primary culprit. Certainly have adjustability from around 50 bar on up. My regs are now set at 115/80 bar. I adjusted the HST adjustment screw 1/8 turn at a time and settled on 5/8 turn out from full in. Shooting 18.1. gr JSBs at PW=7 produces 905 FPS with a SD of 3.8 and ES of 10.
For what it's worth I have three new FX rifles, this Maverick, a Wildcat MK3 and Impact M3. Unfortunately they've all have multiple problems. FX has been great for support, but still... The Impact initially had to go back to the dealer and since then both it and the Wildcat are back at FX USA for the second time. Designs are certainly feature packed, but parts, setup and QC probably could be improved upon, at least from my experience.
Thanks to everyone who read my updates and provided feedback. Happy to close the story on this one, hopefully for good.