That should work just fine Jeff. The ribs I did 2 weeks ago had no liquid and turned out great. Did have a drizzle of peach nector but just a drizzle. They were St. Louis Spares but the principle is the same. Enjoy those ribs and post pics.
If they're anything like the last batch I did they'll give off lots of liquid on their own. Just like you, I didn't add any liquid and I ended up with about three cups of fluid from two racks. Mine were spare ribs, not baby backs, so YMMV. I defatted the fluid and used a reduction as the basis for a sauce. It was excellent.
That said, my max temp is 225. You get up into the 250's+, that's a game change (again, imho)
wrapping them before major rendering is the key,wrap too late and you will have to add,temps being stable make it easier to predict when,I prefer not to but its good either way