Wait, I just noticed this. You cooked ribs at 250 for 6 hours and they weren't done yet? Wow, I don't know how accurate your thermo is, but even if the actual cooking temp was 220, they should of been done in 6 hours with no foil, mop, or spritz.
Bump up the heat to 275-300, and meaty ribs will be done in 3.5 hours.
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)