Relocating the head unit

I have an 89 LX 5 speed. I am thinking about moving my aftermarket headunit up into the center vent position, since with a 5 speed its hard to get cd's in and out in 5th gear. I was wondering if anyone has tried this and how involved is it.

I already have to take the dash out to replace my heater core, so I figured I could just cap the central air vent unit after I cut it down some.
 
I already have a shortthrow shifter on it. I chose the central vent because its a nice, up high position. My headunit is the aiwa mp3 flipdown unit, but if I ever want to go for a screen, having it higher should be a better position.

I am thinking of either capping the central vent tube farther down into the dash, or routing it right back into the heater core area, which shouldn't cause any problems. I'm still in the process of taking the dash apart, but since it has been so cold, I'm going to wait till Saturday (suppose to be 50).