Here's the system I use with it. First the Sekri L1 zip-top.
This is my go-to base layer for about 50 deg and lower.
Next up the Propper L4 Windshirt.
Incredibly warm for it's weight, especially on the move. Worn right over the base layer.
Next the Sekri L2 Gridded Fleece.
This sucker is really warm but also really breathable. Wear without windshirt when you're really humping it. Wear windshirt over it to shut airflow down.