Seems like Mr. Walleye has a good idea for the few time more than 8 might be required.
I think more than 8 would be adding a lot of moisture to be moved through even a full open vent

Maybe just dont rotate the bottom two racks (they will dry first and I dont think the others will retain that much extra smoke after they have started to dry

) and put the extra pieces in on those racks when they are done? Never faced this - I enjoy jerky but am the only one in the house eating it. 5 lbs of eye of the round 1/4 inch thick is a nice fit on the 8 rack technique I have used.
Just an idea but we are not what would be referred to as jerky monsters volume wise.