Flite-Metal
In answer to your question I am fairly confident it will come out at no more than 12oz.
Using a 1500mAh 3s LiPo this 40" weighs just 10oz all up.
Yes the fan, duct and motor weighs 3/4oz more but at 13A it too only needs a 1500mAh and the rest of the structure should be about the same so 12oz is quite possible.
Depron is wonderful stuff.