Couple of things:
as an original ghost owner (who is still looking for replacement parts for internals - valve tube, cup seal, bolt and lt wt hammer) I can tell you that I spent many, many, many hours tweaking Ghosts and that the way to get the best performance out of one in terms of consistent velocity AND numerous shots from a 12-gram is to precisely balance the valve spring with the main spring.
I don't know how springs are being shipped these days, but basically (old skool) if you can use a red and a red or a yellow and a yellow, you're close to that balance.
You want to have the main spring be just strong enough to overcome the valve spring just enough to get your desired velocity. You want to use as little bolt adjustment as possible when doing this.
A couple of other 'tricks'; if the pump arm screw hole still goes all the way through the bolt, use a little non-permanent loc-tite on the threads and make sure its in all the way (LAPCO used to ship some stuff called vibratite which was perfect for this job); you can get as much as a 15-20 fps drop if that screw is loose.
You should also forget about any valve tube smaller than a 6 - if you can find an old nelson 00, get it. The bigger the throat on the tube, the better off you are.
The trick with the sliding trigger (although most of you seem to be playing stock so this is basically moot) is to adjust it so that the sear trips when the forward edge of the bolt o-ring seals the barrel - and just the forward edge. You can get up to some hellacious auto-trigger speeds that way.
If anyone has some extra internals, let me know...