Hi guys, my prosport is currently running at 740fps on its standard set up. I'm going to knock up a delrin top hat and guide. My question is how much preload should I be expecting to need to get it up to around the 780fps mark? I'm going to make the top hat the same length as standard.
Only after a ballpark idea, as I know it will be a case of trial and error.

I'm not really power hungry, just would like a slightly quicker lock time.

Thanks in advance.