Blank canvas, steel sided 40×60 pole barn. Thoughts on insulating, electrical, heating???

Hey all, long story short, I have been planning a 40x60x14 pole building for some time now.
My builder called me with a surprise opening, and its nearly done.

I am a busy guy, and haven't put much thought into "finishing" it with electrical, insulation, and heat.

Opinions on the following?
Insulation
Spray foam?
Roll bat?
Foam board?

Wall finish
Osb?
Obx?
Plywood ?
Rather not drywall

Electrical
External conduit if I do osb walls?

Heating
There is no gas...

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