Since I'm going with a 2 piece removable dash, I was always concerned on how I was going to attach the defrost vents to the top piece and still be able to install/remove the top dash. Fortunately, I didn't trim any of the fiberglass on the bottom near where the windshield was going to go. If I mount the vents to the fiberglass, then they can be permanently mounted and the top dash can theoretically be installed/removed without being connected to the vent hoses.

I marked up the locations and drilled/dremeled the holes and slots.




Next I started laying out the hoses and the room quickly disappears.....


To cover up the slots and provide a more finished look, I purchased a set of covers. These are the Vintage Air VTA-49161-LHA defrost louvers. I spray painted the screws black to match and installed them.