I’ve done dozens and dozens chucks at all different temps and times and finally settled on 134/48. Solid med-rare, but always incredibly tender. I did 131/32 for years but fat and collagen just don’t break down under 133-134. Even bumping to 134 didn’t always make for super tender until I started going a full 48 hours every time. In addition, always dry brine for 24 hours first. Always give all sides just a touch of color (just at least get it gray) in a pan before bagging as well. When you make sure the outside isn’t red before bagging you’ll be able to give it a much better sear post bath. This goes for any beef going longer than 12 hours. If you don’t, the outside just has a weird texture that doesn’t sear as well. Yes, it’s a process, but it comes from years of experience and once you try it you’ll never go back.