Hello Tom,
Nice cook and I would like to make a suggestion for the next time you do this cook.
I think your cook could be improved by turning one of your chickens over to where the skin side is down in your cooker. You know, we all cuss and discuss the chicken skin and how it doesn't come out very well in these types of cooks but it is the most wonderful barrier to keep all juice inside your chicken if you cook it with the skin down thru out the whole cook in the butterflied position. You will see puddles of juice on top of the chicken during the cook and you want to be sure to not turn the chicken over and let all this wonderful flavor run out and into the bottom of your grill. And when you take it off of the grill, be careful not to lose any of the juice and lay a piece of foil over it and give it a little time for the juice to go back into the meat before you pull it. Another thing, do not try to loosen the skin to use a rub under it as we want that wonderful skin to protect our bird when we cook it and don't want to take a chance at tearing it.
I think that if you look closely in this picture, you can see the puddles of juice standing on top of the meat and this is what you want to try to keep inside your finished product. And that so called lousy chicken skin will help you do this and make your chicken better.
Anyway, sure be a good time to try this with one up and one down to compare the two results with your chickens on your next cook.
Dave