I am interested as well about the brine as well... I have seen sweet tea brined chicken offered at one seafood joint near me but have passed on it cuz well you go there for crab not chicken ;-)
The brine was Sweet Tea with various pickling spices (mustard, red pepper, black peppercorns, cinnamon, bay leaf, etc.). No Salt in the brine. I let it rest for 36 hours, then rubbed it with Trader Joe's coffee rub and ancho chili powder, equal parts.
I cooked it on a Traeger Lil Tex at 225 degrees. It cooked faster than I expected. Here is the cooking graph.
Even though the graph shows it hitting 140, my Thermaprobe actually had it at 146 by the time I was ready to serve. I pulled the probe, wrapped them in foil and let them go until ready.