Yeah, 2/3 of a chimney is a LOT of BTUs to start off with. I'd shoot for 10-12 fully lit briqs dumped on top of your pile of unlit coals. As others have said, there is nothing magical about cooking at 225. If your cooker likes to settle in at 265, just roll with it and adjust cooking times accordingly.
Most of my bbq cooks average in the 300-325 temp range recently. I see no reason to go back to marathon cooking times.
The chicken will turn out a lot better cooked at a higher temp too. 325-350 is good poultry cooking temp.
Modded Brinkmann Gourmet. Basic UDS. Rescued 22.5" OTS. SJS Mini-WSM. Stubbs. B&B Oak Lump.
Cannondale 2009 F8 (for burning off all the great BBQ)