I recently had some super soil cooking covered with a tarp. It was still cold until I placed it in 10 gal pots where I plan to let the myco web establish for a few weeks. One day later and the center of the pots are a solid 20 degrees hotter than ambient temps.
I don't think I'm going to try to cook in a giant pile anymore, it seems like the activation is slower. Might as well cook in their "homes" and let the myco web establish, without another disturbance event. If you've ever grown shrooms, you shouldn't shake your rye jar more than once.
That being said, if I can think 6 months ahead I'd go for a big pile. I bet it's like drying bud, where the slower the process the better.