Base Layer Recommendation for Skiing

Snow skiing is a bipolar hot/cold pursuit. You can generate a lot of heat during a run (skiing moguls or anything involving a lot of turns), and then wait in line / sit on a chair as you quickly cool. So you definitely want something that wicks and vents if you do overheat.

I may just put a pair of silks on under the Terramar. That might do it. I am headed to northern Michigan next month, and that place can get miserably cold!

I have recently bought a few baselayer pieces from Kuiu, and have found them to be of excellent quality. The Peleton 97 Hoodie is one of the best layering pieces I own. I would think that paired with the bottom from the same line, they would provide a very warm and lightweight base.  I have one of their merino tops which is excellent, but I prefer the moisture management capabilities of fleece for aerobic activities.  

I X-C and lift ski, and have skied when it was 50 below, but mainly ski in the PNW where can be raining, or at least above 20. Though above treelike with the wind it still can be somewhat chilly,

I like wool pants from an Army Surplus ( often not US but does not matter). I wear a light base under mainly because of the itchyness of that wool. If I am lift skiing I put a ski bib over that for more insulation , waterproofness (for sitting on lift) and rain. For X-C I have rain pants that I hardly ever use since the wool pants have an oil that can easily handle a light rain. That is so warm I have noticed I don't need as much on top, even had people on a Norway trip ask me about why I wasn't wearing more on top, though on our last day I wore every thing I had.

I have put on wt. so those don't quite fit, I hope to lose some wt. so I now use heavy wool underwear and rain pants instead of the wool pants and light base layer, like zeke suggested. The wool pants I good padding for falling as well!

I wear a wool shirt and rain jacket over a light base layer (both usually come off if X-C skiing soon after starting). For lift skiing I have fleece as well, I used to use several more wool layers, but haven't really needed to lately, I leave my tops unzipped or unbuttoned (except the thin base) unless it rains hard or more likely it is brutal on the lift that goes above tree line.

X-C I sometimes take a down coat , mainly for lunch stops (if they are longer than when I am solo) or once in Canada I wore it XC skiing, and have used it lift skiing there as well

Just my personal opinion, Any sort of base layer (next to skin type) has to be tucked into your boots at your ankle. This drives me crazy if they arent tight fitting enough, because they seem to bunch up at my ankles and cause me issues where my boots are locked down so tight.

For some reason the merino wool types have always caused me issues like this.

I'd go with a lightweight capilene layer that is super tight. Then your "insulated" ski pants over your boot, and then a large rain shell pant like zeke suggested.

I think that is exactly the way to go. In Winter Park, temps were about 10-15, with some at times. On top, I wore a skin tight base layer turtle neck, then a Terramar top that was thicker, but also tight, and a thin merino Ice Breaker zip top that was also pretty snug. Over this went a Gobi ski parka that was lined but not insulated with down or the like. I was chilly most of the time. 

In hindsight, I should have gone with your formula: a wicking base layer, a fluffy mid layer, and an insulated outer layer, along with a neck gaiter. 

Layer up. My typical setup for lowers in 0-30 F temperatures is:

A medium-weight sock. I have boots that are only a couple years old and well-insulated. I found that thicker socks actually constrict within the boot, leading to colder feet.
Thick fleece pants. Allows me to walk around without my ski pants.
Minimally-insulated ski pants (not great at stopping wind).

In below-zero weather, I'll add a layer of lightweight long underwear. Above 30, I wear the lightweight long underwear and ski pants (no fleece pants).

Uppers use a similar layering system.

All that said, I've found that if my head is warm, my body is warm. So a thicker hat is key in cold weather. I started wearing a neck gaiter last year due to COVID (pull over my mouth/nose when in line), but I liked it so much I've kept wearing it this year. Especially nice to pull up on the lift if breezy.