I have a BTAS regged 400 and two non regged MPR's.
The BTAS regged gun gets 110 from a 190 bar fill before coming off the reg with a lightweight hammer.
they all get approx 5 or 6 fps shot to shot.
The MPR's as you know will do at least 50 good shots or 70 to 80 useable if practicing although 170 bar fill is plenty as you know.
I would not bother to be honest either.
If you do decide to regg then Tench or Airmasters would be my choice.