Hi Jeremy,
To answer the first part of your question, I don't know if 13.5" high is large enough or not, but IMHO, I think it should be more than enough unless you are painting something extremely large. The other measurements would determine the useability. A very long fuselage or wing might give you a bit of a problem. I guess you could always paint 1/2 of it, let it dry, and then paint the other half.
I made a booth that is 30" wide X 24" high X 15 " deep. It's posted a ways back in these posts. The blower I have is 265 CFM like the one you have. It is more than enough for my booth. It should be plenty for yours.
Hope this helps.
Jim
Main WIP:
On the Bench: Artesania Latina (aka) Artists in the Latrine 1/75 Bluenose II
I keep hitting "escape", but I'm still here.