I've spent a fortune on Gloves trying all the best Technical Musto's Neoprene Dive gloves ect..for winter RIBing..but if it's really wet and cold they all have a Time Limit before they get water logged and cold.
The best I've come up with is using ultra thin woollen under gloves which hold the heat even when damp/wet and do make a Big difference!..and just take a few extra Pairs of Gloves...and change em when needed!
Buying the best Quality Hats and PROPER BOATING Boots are also worth paying extra for too!! once yer hands and tootsies get cold it's bloody miserable!..and can have safety implications.