In reply to Cneifion Arête:
You could try buying one of the numerous N.Wales scrambling guidebooks assuming you haven't already.
Great that you're new to it and super keen, but just get out there and do it. If you get to a point where your making a move and feel like you couldn't reverse it or down climb, then either bypass it (usually doable on most grade 1 & 2's) or walk away and return with someone more experienced with some kit etc
Sorry cant help you out on main gully are you not thinking north or little gully or nor nor gully or south gully?
Have fun