Blank canvas, steel sided 40x60 pole barn. Thoughts on insulating, electrical, heating???

we did the in floor in our 36x60, spray foam would have been the bomb! just too expensive out in the sticks. we had quotes over 10K.
2" high density under the slab, fiberglass bats in the walls covered in osb ( I would have done plywood but, it was dads build so I let him do it as he wanted.
if you heat it at all make sure you put in a ceiling. first year we fired up the boiler and ran the heat it used up a 250 gallon tank in 2 weeks!!!!
shut the system down until the ceiling went in the next spring. same 250 gallon tank lasts almost the full year now on Really cold days. we keep it at 45 as we only store our cars in it. we have a unit heater to raise the temp quick if we need to. just remember furnaces need to usually be 8' off the ground for code.

also any lifts or floor drilling you will want to have an idea of before the tubing and concrete go down.
not fun when you drill into a tube!