Alex wrote:
Thanks for any suggestions,

Congratulations on becoming a ham. I have a number of ham friends and
I'm jealous of their skills and knowledge. One day I may have to go for
the license myself.

Several of my friends have set up their 'shack' just as you plan -
building a workbench for the equipment and cooling with thru-the-wall
A/C for the summer and overhead radiant heat for the winter. It seems
to work for them, but the temperature extremes don't approach those that
you might see in Minnesota or North Dakota! I'm not sure where you are
located.

Good luck.