Had a shop in Alberta with 60 amp service, was fine for everything, except the plasma cutter. When the compressor would start it always tripped the breaker, then walk across the yard and into the basement to reset it. Got tiring after a while. lol
I'll second running conduit. Adaptable as time and things change and a lot quicker to do than buried wire and having to cut all the box holes in the sheeting. The PVC stuff is quite reasonable priced and really quick to instal.
I've been framing my buildings with 2x2 horizontal strapping, either inside or outside depending on the siding. If board and batten strap the outside then sheet. A 4 inch bat split in two fills between the battens. This gives a thermal break covering the studs. My current shop is two story, the bottom floor stays at 18 - 19 all summer with the thick walls and the concrete as a heat sink. Causes issues when welding, can't open the doors to let the smoke out on hot days or the warm moist air causes condensation on all the tools. Had to install an air exchanger to vent the smoke and replace with drier air.
Radiant floor heat is nice, installed it in the shop but can't seam to control the temperature swings here. If we get a few cold days the floor warms up to compensate, then it turns mild and the shop is too warm for a week with the extra insulation. Works fine in the house and upstairs shop with the wooden floors. They have less thermal mass to control.
Greg