Randy,
I do have the defroster vents, just didn't have the hoses or fittings in the picture.
I made a fitting from plastic pipe that fits the heater on each side rather than use a "Y". If you have a Hurricane or Maradyne heater, you'll see a couple CapPlugs on the bottom rear of each side. I connected my hoses there. I have the under-cowl fittings from Vintage air that bolt to the underside of the body, with defroster vents on the upper (outer) side. The heater has three doors on it to control the air outlet. The defroster vents will be on or open all the time. The heat vents can be closed if desired.
I had to carve up my glovebox mold to clear the hose on the passenger side. I'll take a picture and post it along with the others I'm working on. It's tight but it fits and you only lose a small corner inside the glove box. My box is essentially the same size as the door to it and about 12" deep, almost all the way to the firewall. I left a couple inches clearance since I have a number of wiring items just behind the glovebox.
Pictures at 11
Paul