Hi Dan. You eluded to the wind during the winter on the ice. With your hut being approx. 18 inches off the ice (at least for now), you may want to consider making your floor holes the same diameter as a five gallon pail. You can then remove the bottom of the pail and slide it down from your hut as a sleeve to the ice surface. Works very well at blocking the wind and prevent hole blowing in or freezing.
Good luck with your build, looks great.
PS I agree with black paint for the hut to absorb sun heat and for visibility on the lake. Reflective tape will help the snowmobilers for sure.
Cheers
Craig