You can do it in 6 hours if you kick up the temp. You'll probably need to run at 325 or so. I have no idea about timing on the ribs at that temp, however.
When I cook in my WSM I bury 4 or 6 fist sized chunks at various points in the charcoal in he ring and I put one in the chimney to start.
"Ron Rico, Boss. You can call me Captain Ron..."
The Naked Fatty!
FEC-100/BWS Party/Memphis Pro SS/PBC/LBGE X 2/SBGE/Mini BGE/Nomad Pellet-matic/Good-One Model 42/WSM X 2/Cookshack Smokette 008/Weber Performer/Saber Cast 500/Weber Gasser (RIP)/Weber Kettle X 2/Weber Smokey Joe/WGA/UDS/Coffee Roasting Gasser and a pickle
Remembering a friend