Ngl I kinda disagree with blaming the wrench here. "Off by almost 18 percent at lower ranges" sounds like a calibration issue for sure, but a $35 rental from AutoZone isnt gonna be magic either. Those floor models get dropped and abused just as much as your home one. Maybe the real problem is you were using a click type at all for head bolts, those things are sketchy on reused threads. Ive had better luck with a beam style or just going by angle method on stuff like that.

Weren't you worried Coup would just hype people up too much for the heavy stuff?

Kinda funny cause I used to think those guys were just old school for no reason. I'd watch BBQ videos and think "they're just being stubborn about temp control, I can do better with my electric smoker." Then I sat at Franklin's and watched that one guy just chill, drink coffee, and poke at the fire every 20 minutes while the brisket did its thing. It hit me that the whole "trust the stall" thing wasn't about being patient, it was about not being scared of the meat. Now I don't even look at my thermometer till like hour 6, just set a timer and go nap. And yeah my brisket went from decent to actually good once I stopped babysitting it like a nervous parent.