I’d just do what Mike suggests and prep the night before, wake up early and put them in and go back to bed. I’ve cooked 6 racks of baby backs in my 3D and the time was the same as if I cooked 1 or 2. The other thing, I’m guessing the 5 is a digital control, correct? So that allows you to cook the ribs at a higher temp, 250-275 and will shorten the cook time. So you could also try that.
You’ll see why this is called lazy q at it’s best after the first cook!