I've used the Bradley to make spare ribs many times now.. but this time I have to do 4 full racks.. How much time is this going to take; to do 4 racks completely in the Bradley?
Which Bradley do you have?
Is it 4 racks of ribs or 4 Bradley racks of ribs which could be 6 rib racks if you split the ribs in half and put 3 half sections on each shelf.
Now for the most important question, What temperature do you smoke at? 200, 220, 260......
Where do you monitor the cabinet temperature at? Next to the bottom rack will be 30 to 60 degrees hotter than the very top rack. The bottom back rack will cook much faster. Rotating is good but does decrease the average box temperature due to recovery time.
Overall, 7 to 8 hours should be sufficient if you monitor your box temps for a middle rack temp average of 220 deg.