When I do the potatoes on the grill, I cover them in oilve oil (or any cooking oil for that matter) and sprinkle sea salt on them. I usually run them at 350 until they feel done to the touch. It's usually about 45 min or and hour. I was winging it this time since I had never cooked them on it when I did a reverse sear. So, I put these on about 30 min before the steak and the temp was 250. By the time the steak hit 105, was pulled, the grill temp raised to 400+, and the steak was seared....they were done. I like doing them this way. The skin tastes really good and smokey and it almost gets a sweet taste. If that makes sense.