Nice job Wing Nut...! You got the short end of the stick on that purchase, at least initially. And if someone other than you had bought it, that didn't have your mechanical skills, it would have been a majorly negative experience. But now the gun is totally resealed, all Viton O-rings, firing valve cleaned and polished, regulator disassembled, all parts cleaned and polished, O-rings replaced, HST, hammer, etc. cleaned and polished, and trigger cleaned and adjusted. Not much else left to do, and the little Cricket is good to go for years to come. And, now you know your gun inside and out, which means you also know Vulcans and Taipans inside and out. 14 for an ES isn't bad, and it'll probably get better as you lead in the barrel and shoot it more. The reg. that you rebuilt and polished the washers, super clean barrel, firing valve and spring cleaned, etc. needs a little time to break in. Try shooting a string again after a tin of pellets, and adjust the speed to right around the 865 to 870 fps range. Now take it to your club this weekend and beat all those RAWs and Thomas guns in the 25M BR...
I'm going to send you a new Hammer Spring, since the one in there was very rusty, and even though you cleaned it I'm sure its weak, since half way in with stock reg. pressure should shoot around 900 to 910 FPS. Once you install the new spring you won't have to turn the HST in very much to get to 865 FPS...