Plastidipping the roof of my disco

I have been considering doing the roof of my disco in white.  I recently saw a Toyota Landcruiser with a similar Burgandy with white roof combination and I found it quite fetching.  Before I spend the money on a full on respray, which the truck needs, I pondered using plastidip to see if I like it or not.

The question:  How many cans do I need to do just a roof?  Is there a formula I can look up?

i would personally start with two, maybe 3. 

when you do the final job, you could also consider doing a roll-on paint. I did my roof with foam rollers and some self-mixed rustoleum professional (wanted to darken the sand color a bit) and it came out really nice. IMO I like the light textured look vice a smooth finish.

While mocking up color ideas I found that having a light-color roof looks way better if your wheels match (i.e. white wheels on your Rover will look awesome with a white roof...)

btw, here's what white looked like (this is primer, but whatever)

For your consideration : there's pigments you can add to sprayable Dip that color changes with heat. Think Hypercolor shirts from the 90s. 

I always wanted a black to white shift. Think black below 60 degrees and whit above. Why. More ideal internal temperatures.

In reply to Appleseed :

That would be really cool!!!  I could see a whole car done that way. Stays cool in the summer and warm in winter. Also a black car in winter with snow is more visible and a white car in the summer is also readable visible due to darker surroundings.