Hi pianogun
I would go plenum route as to keep it compact " I know it's more work for you but your obviously talented on the engineering side.
Have you opened up the transfer port at all.
As you may know these guns were never meant to be a power house to start with.
Its been a while I messed with mine now but I think regulator was about 1300psi which gave me about 15ftlbs dialled back to 11.5 ftlb uk limit.
It took a while to get it all singing off the same hymn sheet .
Shot count is ridiculous compared to the standard tube lol.
Mine is 22 caliber and barely audible at 10 yards" just the hammer sound
If you haven't already try some slugs through your gun you might be surprised even at sub 12ftlbs .
The only other thing I can say is set the trigger correctly as you can lose fps if it's not done cock on.
I think you and your little old lady have got some good shooting times coming up.
Them nats knackers ain't looking so safe anymore round by you lol
Please let me know how you get on
