Charcoal Griddles: On a charcoal grill you need to make sure that the griddle you get allows for sufficient air flow. It should not fit the grill surface too closely otherwise the fire will be starved for oxygen due to low airflow. Otherwise you can use a griddle on a charcoal grill as easily as you would a gas grill. One thing to think about however is hot and cool zones. Do you want to have a very hot section of you griddle and a medium warm section? If so you will need to bank more coals on one side of your charcoal grill than the other. With a multi-burner gas grill you can have one burner on high and the other on medium to create these different cooking zones.