I think i saw a thread of yours regarding your troubles, I hope you get it worked out. I polished my barrel last winter, I think it helped with velocity consistency but it was already accurate. A longer while back I had my trigger sear break in two and decided to have a new one machined from hardened tool steel, it's been solid ever since.
Maybe you could post some pics of some of the internals as you take it apart, might help give me a better idea of whether my wish is possible. I wouldn't imagine the holes between the main tank and plenum would matter too much, if the reg was gutted, it would all essentially be all one air reservoir no? I wonder what would happen with an upgraded power valve and the reg set to 250 bar. Don't suppose it'll go any higher will it? I assume it isn't supposed to.
Maybe one of these days you should try some of my .460 slugs