Maybe I missed it -- I see foil over the earliest coals and later it's not. This was to prevent fat from hitting coals? How did they burn correctly (and without burning through the foil?)
I use HD foil to prevent any flare-ups, and the fat from hitting the un-lit charcoal.
My thinking for this is that maybe the charcoal won't lite-up if it's too saturated with drippings, slowing down, or stopping the fuse.
Once the rib racks had shrunk, and were not over the coals, I removed the foil for the final stages ... last hour , maybe a bit longer.
The charcoal continues to burn under the foil. No, it does not burn through the foil.
This method works great! I recommend it.
One other reason ... I can fit more on the grate without fear of charring the food.