Matt, so close. 195 can work, but not always. I've read folks say 190F. I shudder when I see that. I tell people an IT of 200F before they should even start probing for tenderness. I've had a chuck go to 207 IT before it was tender enough to slice. With tough cuts of meat, longer is better.
I'll share a story. Back when I first started cooking pot roasts on the stove and in the oven, using chuck roasts, I basically gave up because I could never get them fork tender. They always came out like a brick. My wife went to a church event in Texas for a funeral and the pot roast (chuck) they served at a dinner for the family was tender and juicy. My wife asked the little white haired lady her secret. Under her breath she said "Honey, just cook the snot out of it." After that I never had a pot roast that wasn't juicy and tender whether done on the stovetop, oven or the smoker. I've only had one fail on my very first 2.5 lbs smoked chuck roast when I pulled it off the smoker after 6 hours and the IT was only 187 or so. It was a brick. I bumped the IT up and have smoked many, many chuckies since then, one of my favorite cuts to smoke.
Longer is always better with tough cuts. Take that dry as a desert chuck roast, add a little water or beef broth to a roaster, cover it with HD alum foil and cook it in the oven at 350F until the IT is 205 or so. You'll save the roast. The collagen has to break down some more, and that's where tough cuts get their juiciness and tenderness.
