Do not cut more holes in the bottom. Open your bottom and top vents wide open. Pile your coals in a C shape towards the back of the grill. It helps to use a couple baskets to keep them in place. Make sure your coals are lit really well before dumping them into the C shape. After doing so you need to make sure you are using good quality wood chunks/chips to throw on the coals as you go. If your coals are hot and the wood chunks are good then they will catch fire and raise your temps quite a bit, but you have to keep fueling the fire. Ideally you want your baking stone over 600 degrees. If you have a IR thermometer you can tell or if you are looking at your thermometer on your lid just make sure it exceeds this temp a fair amount.
My advice though is make sure it is a black kettle you are using because the high heat can be hard on the porcelain. No sense in being hard on a looker. Also, look into a KettlePizza or Pizzaque. I have the KettlePizza ring, Tombstone, and baking steel and it cooks pizzas in 3 to 5 minutes easy. Back when you could actually have parties I have cooked well over a dozen in a single cook. However, if you are going to go longer you might need to do more charcoal and keep it plenty hot.