Seems like you did pretty well. Personally, I am a water in the smoker guy, as I believe that moist air in the smoker gives a better cook and texture. But, that being said.
If you are going to foil, add a little moisture, either juice or broth, to the foil. Just a few teaspoons, that will improve the bark when you remove them from the foil for the last 30 minutes or so on the cooker.
At 275°F, you should have gotten great texture to the top of the ribs, even without spritzing, is the top of the cooker full open, you are getting good flow through the cooker?
I'm feeling bearish, and I'm packing a Wusthof Grand Brisket slicer from MABA
"perhaps...but then again...maybe not..."