Hi mikecarr, you dug up an old post !!
If I remember correctly davemich found that if he shook only once in 24 hours, that the ash accumulation on the grates slowed his burn rate by about 30%,
He also got Hitzer to send him a draft restrictor that installed in the outlet of the stove. Dave's draft was VERY strong, so this worked well for his application, it may not be for yours.
I'll email dave to see if he can respond to your questions.. he's not burning in the Hitzer this year, he has a 16 month old sone with a high degree of curriosity, and Mom won't let dave heat with the stove for fear of their son getting burned.
Take care, greg L