Well, I put four halves on each kettle, and learned to use more lump than you think you'll need if basting a lot. My lump ended up burning down to not as much as I wanted and basting put out some coals. I adjusted though and moved chicken around and it just took longer. I could've used one kettle, but I'd use a LOT of lump. Three chickens max per kettle would be better.
Lessons learned:
Use LOTS of lump.
Marinate longer...at least 2 hours.
Yuengling Lager goes good with Roadside Chicken.