I'll defer to the more seasoned smokers, but in case they don't come in during your cook ... I think the ribs can probably handle 275F just fine ...
I think you'll be stoked w/ the final result, even if your temps get a little whacky for a bit.
I'm doing my next brisket at 325F, for instance, I think ...
I saw conflicting posts recently, one said the temp at the grate was higher than the dome, the other said the opposite ...
I guess it probably depends on a lot of things - vent openness, diffuser, etc ...
Can't wait to see the results ...