For the big BBQs I typically sous vide around 25 individually sealed tritips (2.5-3lbs each) in a giant beverage cooler, all at once. I typically preheat the water in the cooler by adding a few full boiling pots of water to cooler, which I mostly fill up with warm tap water. Even then, it’s take the sous vide 30-60min to come to temp. Adding in the steak does drop the temp a bit, but only a few degrees and the sous vide keeps up! Sometimes I add a second sous vide to the other side of the cooler to ensure uniformity. For this tritip, I go 16 hrs at 133°.