[bagmister]

Greetings!,
so i have a ford F-150 dedicated CNG. i average about 17 to 19.5 mpg it's a 2 door long bed (8 foot roughly) = 98" long. 72" wide cab stands about 22" tall from top of bed line. if i were to draw an imaginary line to the top of the cab to the top of the tailgate at a straight line it would be 106" long. I was looking into making an aero cap. I want to build it from scratch so i decided to go with wood seeing as that is what's cheaper and i have access to it. But i have no idea how to add a 3rd brake light to it. What would be the most efficient angle? can i do a straight back drop?(tear Drop?) maybe an arch?
I'm thinking of doing a cap similar to the red 06 canyon i saw on these forums. I've been poking around for some time just decided to start. i haven't measured the angel that the truck cab is tapered to. but the top of the cab is 50" roughly.
What do you guys think? I would like to have this done by April. I will be driving down to Las vegas from where i live near salt lake city. a very good chance to test experiments. But also out of necessity. There are stretches were the next CNG station might be to far... hence I need to get more mpg out of the truck. I have noticed the engine likes to cruise around 55-60
for those interested.
the body is the 1997-2003 body style
Engine is 5.4 2 valve modular/Triton engine from ford.
I'm building a cost chart and i think I'm going to be spending around 3-400.
any suggestions would be welcomed.(I'm new to this)