Dracula, thanks for your compliment. I like participating in the eng-tips forums. I don't know if my posts are of value, but I can assure you that I learn a lot from this website.
Now, some thoughts on charcoal drying with hot air.
There are factors that may dramatically reduce the activation energy to start a fire. Among them one can mention: the unknown pore surface of the charcoal particles and their size distribution, the amount of still occluded pyrolytic organics that may have low ignition points, the various possible catalysts present, the way the charcoal bed is arranged, the contact time with hot air.
Although evaporating water is bound to cool the gas and the charcoal, it may sometimes act as a catalyst to enhance combustion. Under special circumstances I heard that even CO2 may oxidize charcoal to CO.
Thus, to be on the safe side, whatever a book might say about charcoal burning with air at various temperatures, I think that Guidoo's advice on trial bench tests is the right approach, and deserves a star for that.