For me, I always wear safety glasses, so the hassle is keeping them clear rather than drips and spray in the eyes. Peak on helmet helps a bit.
Waterproof top, let the legs and undercarriage get wet.
Sealskins socks when I know it's going to be horrible, not the most comfortable, but better than Porrelle Drys for comfort and keep feet dry until water gets in the top, even then keeps them warm.
Double bag clothes, carrier bag, pulled tight and twisted closed upside down in second carrier bag done the same. Kept stuff dry 99.9% of the time when I was motorbiking and yet to fail cycling. Could use a dry bag, but a bit overkill.
Leave a dry set of clothes at work anyway, I carry in the clothes for two days time with me, wear what's already sat in the locker that way I know it's dry.