English Showing - numnahs, bridles?

You see people with half numnahs and the full ones which go all the way around which do you suggest? I'm looking at starting to show more and was wondering about the bridle. I'm just starting to get my horse to bring his head down and go properly and i have him in a bridle with a dropped noseband or a hanoverian bridle would this be suitable to show him in, in ag shows in the open and pony club sections. If not what about the flat cavesson bridles?