Concerned it may be dry and soak up all the thin set moisture too quickly and dry too fast any thoughts?
Don't over-think this process, you'll be fine.
B-C with Green strip- ext ply- (cost over 20 bucks a sheet)-
Like the "green stripe" is supposed to mean something to me?
The green stripe is an invention of the big box in an attempt to help their illiterate employees recognize the differences of plywood from a refrigerator.
I have about 400 sqr ft put down per the ditra reqts (called the company).
Well then you don't need us anymore.

Good Luck!