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

I installed everything myself for the floor heat. I divided the 30x60 heated area into 5 loops w 15" spacing. The pex tubing is 1/2" into manifolds and cost was $540. The heater unit and pump invertor panel was $2400. These prices were from 2008-2010 and purchased at Menards. The heater is electric off-peak demand control. The gas heater was higher hardware cost but would be more cost efficient to run if natural gas available. I insulated edge of concrete but should have insulated at least 4 ft. in from edge.
thanks so much! seems like the pex part isn't too bad. we don't have any gas out here so would have to look into an electric heater. I'd assume that isn't as "easy" as residential grade hot water heater. I'll keep researching. thank you.