Planning my shop Build-out for next summer, looking for advice.

You can buy insulation in a big blanket that goes around the roof trusses right on the underside of the roof and down the walls. It insulates better cause there are no 2x4’s to transfer cold to the inside wall. On mine I ran siding faced plywood up 4 feet on the inside walls and the rest metal siding in including the ceiling. There is 10 inches of blown in insulation on top of the ceiling plus the blanket insulation on the underside of the roof. This is where most of your heat loss is. Don’t forget to put a vapor barrier between inside walls and insulation.