If you have filled the chimney with charcoal, you have a problem, but, it is manageable. Put the coals in your cooker, it will spike in temps a little. Shut down the intake completely for 10 minutes the crack it open. Temps will be in the 300f range, put meat on. Since you started hot, and have used charcoal for fuel, you'll end up with about 5 hours of cooking time for a normal load.
I'm feeling bearish, and I'm packing a Wusthof Grand Brisket slicer from MABA
"perhaps...but then again...maybe not..."