Great modeling and really you are sick man. How many polies the balloon have? Why you don't use bump maps for your balloon, it safe more polies and PC recourse, of course if your computer is fast.
Anyway I like your model and good luck with it Can't wait to see the ship
also a suggestion to make different material ID's to the squares an then randomly assign the main material with different brightness and contrast settings, because they were originally different (made from scrap i think ).
U can easily do that with souldburnscripts (if i'm not mistaken) it's a free pack of scripts with material id randomiser (or something like that) and also there's ColorCorrect plugin to change brightness contrast and bunch of different settings.
(it's just in case if u didn't know about them, but i somehow doubt u didn't, to find them just google it )