Thanks Leon and Jase.
Jase, the gain is usually around 46 to 50 so I shall experiment with that and see what happens, also the focal reducer has extenders which allow to image at f/3.3, f/5.0 or f/6.3 so I'll investigate that area as well. I assume imaging at a higher f value would increase the critical focus zone.
Thanks for the advice, and now I have a little project to work on, I see the clouds are rolling in on cue.
Cheers