What would be an alternative cooking technique for the Orion Cooker to get more tender ribs?
I haven't used an Orion, but I watched their video and I feel like I've got a pretty good handle on the concept. I'm like you, I like ribs super-fall apart, and usually a bit saucy. I would try braising them in a big roasting pan in the oven a couple of inches deep in liquid for two hours or so (just at a simmer, don't let the liquid boil), before putting the racks in the smoker. For the liquid you can get as experimental as you care to.