Slow cooking Danish Back Ribs?
I don't have any personal experience with them, but my understanding is that you're right, they're leaner. They also tend to have less meat on the bones and dry out quite a bit easier than domestic baby back ribs.
How did you come by these anyway?
I'd still smoke them using my normal smoking method and, if I had more than one rack, I'd smoke one without foil and another foiling a couple of hours into the smoke then compare the results.