Last chance to put in that heated floor . . . I worked for IBM in Charlotte, NC back in 1982 and unless the climate has changed drastically, I don't think a heated floor would be your best option anyhow. I recall having to wipe the inside of my windshield every morning from May through November on my drive to work until the defroster heated up because of the condensation. Might be best to have forced air heat to keep the air moving. I've got a couple of ceiling fans in my shop that run 24/7 during the spring and fall when things start sweating in the job. Really does a nice job keeping the condensation off the cold cast iron.
You are going to love the space, hope the weather cooperates and you get some cement down. Great looking area for a shop!
Bruce