I'm going to agree with Riz58 for what you probably want to do next, although I like to cook mine at 270. The key thing I think is usig the cooler to get it finished. If you are good at knowing the proper tenderness probe test then you don't HAVE to cooler it, you can pull it off and just let it rest naturally and slice it. However, if you don't have that nailed, then the best bet is to get it towards the 190 range and wait for the flat to start probing tender. Not "hot butter" tender, just more tender, starting to loosen up. Then wrap and put in a cooler to keep hot for 3 hours. It shoudl finish up during the rest. Keep in mind this probe test is still subjective, but you may recognize "starting to soften up" a lot better than the perfect "like butta" tenderness probe.
Good luck. Nothing trumps experience...keep cracking.