I think you will have to use some common sense here.Do you want the FEC to do all the work and you just take out the perfect slabs?
Like they say,maybe 3-4 racks per shelf.
On the FEC ,you will have hot spots,and you will see where airflow can be constricted.Yes, you can rotate whole racks,and move heavy slabs to hot spots.
Guys cooking large volumes on a charcoal cooker will have to stack slabs and rotate for even cooking.Smart cooks do well,on any cooker.
You pull as done and rotate as needed,like ANY rib cooker.You might double the racks per shelf.
With 4 rib racks we rotate and pay attention, for 40 plus trimmed slabs.The cooker handles this easily.
Yes,you can cram more,like any cooker,but the cook determines how they handle a quality product.With seven racks can you pay attention to when ribs finish?
You must determine when to pull your product.The FEC can be cranked to do the cooking part of the project.
A cook wanting to pay attention to the cooker,rotate and flip as needed,properly trimmed,can layer slabs.There is no rule I know of that slabs can't touch or be stacked.
Yes,a good cook,understanding his cooker,paying attention to his product,ought to easily handle forty slabs at a time.A cook in need,that pays attention,might do half again as much.
Have fun and watch the FEC and you should do fine.
Having a fine cooker like the AQ is certainly a luxury,even as a holding oven.It allows you the leisure of not having to work yourself with just the FEC.