One suggestion is to not try to chase temps. If the drum wants to ride on the 260-270 zone then let it ride. You're really in good shape all the way up to somewhere around 325* IMO.
Also, when they're done, they're done, get rid of the thermometer for ribs. If they pass the bend test which Wampus described after only 2 hours they they're done. Don't worry some much about sticking to specific time regiments, they're good for general guidance but shouldn't be taken as gospel.
Overall I think you may have overcomplicated things with all the techniques you're trying to put together. If you're just learning, sprinkle them with some rub, wait till the drum settles in to the range it wants to ride at, toss them on and walk away. Check them after about 2 hours and then every 45min-1hr after that.
Traeger lil Tex, 2 Weber 22.5", UDS
Mop, Sauce & Two Smoking Barrels BBQ Team
They call me "Dave"