In place of spritzing, you could consider putting foil around the ends. Or, try pulling off the grill wrapping and putting in a cooler for an hour once the ends look like they are done for your liking. Spritzing is an option, but I'm not sure it will have the impact you desire.
If your grate temp ran a little hotter than 275°, turn the temp down 5-10° degrees on the controller. That could be why they dried out.