For a mid layer you should look at synthetic or merino. I have a lightweight fleece.
A basic rule is to never wear cotton (hoody) if you are wanting to stay dry/warm. I will wear a base and hoody once it starts to warm up though, because then I don't have to worry about freezing my ass off.
My mid layer right now is an arcteryx covert fleece. Expensive shit but very well worth it.
I am usually fine in a patagonia #3 baselayer and my lightly insulated jacket, but for really cold days, I drop to a patagonia #1 or #2 baselayer (thinner) and add this new bad boy r1 hooded fleece, the hood fits under my helmet and covers part of my face.
I am pretty much a patagonia whore when it comes to baselayers and fleeces