In the summer heat, I like to use my outside grill as an oven. You can make your grill an "indirect heat" oven by only putting charcoal on the very outside of the grill. Then, cook in the very middle. I also use a tin shield about 5 inches tall that makes a ring around the grill. You want the heat to go up the sides without hitting the food directly.
Those taters will cook perfectly in the grill that way. The smokey flavor just adds to the dish.
Confirmed Sushi Addict