Thanks for the input guys.
I am still trying to get the rifle running sweet. I have just fitted a vortek O ring kit and am still playing with piston weight/preload etc. The O ring is quite a snug fit, I'm not sure if I can do anything about that?
The standard TX kit was really low on power (I think this is because it is for mk2/3 and I have a mk1) so I have now fitted the HO kit. Without preload or piston weight, just with a small delrin top hat , it is currently sitting at about 765fps with JSB exacts.
It's running bone dry, without any grease at all at the moment, I may keep it that way because there is no twang/vibration. It has a nice snappy lock time without being to harsh.
I haven't scoped it up yet, so I suppose I won't know how smooth it is until I have shot at a few targets.