Base layers for cold rides?

[hlthe2b]

1. I walk 4-6 miles every morning before full sunrise and last week was zero-8 degrees.

So, while I can't speak directly to the specific differences with cycling, I walk hills so I do build up some sweat even just walking. So for me, a breathable technical dual-ply first layer that wicks and a minimum of one fleece (or a second one if there is wind or near zero temps) and a wind-proof layer or goretex depending on precipitation. A scarf that can be pulled over my face, an ear-covering headband and a thick knit under-glove with a pair of deerskin-fleece mittens on the coldest days. I usually wear my winter-proof reflective bill Nike baseball cap under the headband as the bill keeps a lot of icy snow and wind out of my eyes. I'd bet both of those issues are important for you on a bike. I wear wool tights under my pants on coldest days and that seems to suffice.

You may not be experiencing the same extremes, but a single layer fleece over a technical wicking layer ought to work. Add a windproof jacket if windy or an insulated vest otherwise.

I'll be curious about what more specific advice you get to the contrary...