Beauty!
I have not seen the 251 spec, but I really like the time and temp.  I have seen ovens that have been off by 20 degrees or more which is why I go on the high side.  Folks really disagree with the 30 minutes. Again I think it is way good.  As to time increase per layer the increase depends on planes.  In measuring weights of material in baking it was more challenging extracting moisture between and adjacent to planes.
Relative to the volatility nature of the adhesive; it is the fragile nature of the material that requires less is best.  Thickness and location.  I only use it on cover coats, use 1/2 ounce to limit the fill requirement and terminate just within the rigid; keeping that area PTH free.

Thanks Steve, I am off to the IPC book store.

Sincerely,
Brad