Nice, thanks for the info again...it really sounds impossible to mess up. May give it a bash this weekend. I weathered away my MK18 totally differently and wouldn't do the same to my scar so thanks for the help!
As for the rubber, was using the stock with a madbull 6.03 inner (I've got the full length barrel in) and wasn't too impressed. I've now got a prometheus purple rubber and have PTFE'd the barrel and hop unit and am a lot happier now! It's running at 335 FPS (with 0.2's) and I'm using 0.25's in it if that helps.