I did all the work, I'm an aerospace machinist by trade. The tune was pretty simple, i polished the section of the barrel where the cocking assembly rides, polished all friction parts, made a new de-pinger, the new shroud, re-centerd the barrel over the transfer port and tuned it for accuracy with 18.1 JSB's using only the HST adjustment. The rifle shoots single .22 cal holes at 25 and pretty consistent groups ranging from .300-.400 CTC at 50 yards with a 12x scope. The JSB's chrono at 904 AVG. I have a full shot string printed out somewhere that I need to find. Its quite a fun shooter for sure. VERY, VERY quiet, and easy to shoot teeny groups with.
I love tinkering with stuff, just re-aligning the barrel / transfer port picked up 15 fps for me. The rest just made the rifle a joy to shoot. The loading / cocking process feels like its on ball bearings.