Have you ever considered some waterproof overmits.
A fully waterproof glove has one huge disadvantage, the stitching and seams along the fingers can prove a weak spot.
With an overmit, there are far fewer seams to allow water ingress, and you are almost spoilt for choice.
How often is the weather severe enough to warrant fully waterproof gloves, not that often, overmits covering your standard gloves may be a better solution.