Just made this for a fourth time and may be starting to get the hang of it.
First off, I worry about using too much marinade because I haven't really figured out a good way to get rid of the unsafe leftover marinade -- my understanding is that if I dump too much oily stuff down my septic system I can get a layer of oil across the top and kill off the ... um... anaerobic bacteria... which don't need oxygen ... so what's the deal... ???
Anyways, first time I made two batches of sauce, used one for marinade and one for basting / mopping. Very tasty but about 90 minutes to cook, with coals half-drowned by the sauce. Second time I made a single batch, held some back for basting, and rearranged the chicken in the marinade to make up for the reduced amount. Basted with a brush -- worked ok but maybe a bit light on the flavour.
Third time I had lots of coals and put a pot of sauce on the grill so I could dunk the pieces in hot sauce. Worked better, cook times maybe 45 minutes, but a few of the pieces ended up undercooked. I didn't pay attention to which ones, unfortunately.
This time I made a single batch of sauce (again) but poured it into a leftover plastic "spring water" bottle rather than into a big bowl. Chicken marinated in a freezer bag with perhaps 1/4 batch of sauce. That was about right -- I had about 2 tbsp left over in the bag after an hour or so in the fridge. The chicken was cut up in 10 parts again -- legs, thighs, wings including a bit of breast meat, breast cut into quarters -- since that seems to produce nicely grillable pieces.
For cooking, I started with a pot on the stove and dunking but after a while noticed that the sauce in the pot wasn't very hot so started to wonder about cross-contaminating with chicken bugs from earlier dunks. Poured the remnants of the pot over the chicken and switched to dribbling sauce onto the chicken from the water bottle. I also stayed close to the kettle (22-1/2"), took the lid off completely, and kept the chicken moving and flipping over the coals.
Folks, this is the way to do it. Total cooking time was just over 30 minutes and the chicken was perfectly cooked and VERY tasty. The legs were not quite cooked through, so next time I'll either start the legs 5-10 minutes before the rest or try this with half chickens and see if that equalizes the cooking times between the various body parts.
For the miser or septic tank worrier, I used 1/4 batch for the marinade and 1/4 batch for dunking and dribbling, so I have at least 1/2 batch left over in the bottle for next time.
Cross-thread note -- the 14 oz cylinder in my Performer finally ran out. I figure I got a dozen or more lightings plus some tinkering, averaging 5-10 minutes per light. YMMV, of course. EDIT - for clarity, "cross thread" means this section is applicable to another topic which I was unable to find, not that I cross-threaded the propane cylinder