I've just got a good jacket from Ground Effect that works well. It has pit zips and a hood that fits under the helmet. I just wear a pair of their Daddy Long Legs tights in the rain.

My legs don't get cold even though they get damp and the jacket works well. I tend to wear wicking shirts which don't hold the water close to the skin underneath. I'd like to wear merino wool tops but I am mildly allergic to wool.

You are not going to stay 100% dry in the rain. If you wear 100% waterproof gear you will still arrive wet, just it'll be sweat not rain. I'd suggest that on wet days wear some clothes that will keep you warm even if you are damp.