My feet get really warm when doing alpine touring in ski boots.
I have been using Smartwool summer weight socks and even these seem like too much. I was thinking of going to a liner sock only.

What is your go to?

I tour with smartwool mountaineering socks or standard ski socks. Although, no thinness of socks is going to make up for the fact that you're exercising vigorously in insulated ski boots that are designed to keep your feet warm.

You could always try keeping the power strap and top buckle loose for added ventilation and pants up above the cuff of the boot. My boots (Maestrale RS) have ventilation holes in the cuff, I doubt they actually do much.

You probably don't want to fenestrate the boots (unless you have a separate pair for winter) nor remove the boots' insulation (risks destroying fit and comfort), so your next-best option is to ventilate your legs: wear shorts.

Personally I use plastic mountaineering boots.