@MikeRocksTheRed . You are a wealth of information! Been poking around the forums and found a bunch of your posts will help me up my game.
I agree I don't need the internal lid but I want it for reasons you mentioned... use less fuel... if the dome of the lid is open, I'd bet there's a 75 or 100 degree difference between the top of the dome and the surface of the pie.
I was pretty determined that I was going to try the lid modification (cut the opening) and give that a try. But the more I think about it, I think I'm going to buy the Kettle Pizza base model then using a spare lid, drill a hole in the top, drill a hole in the center of this
https://www.amazon.com/Weber-Smokey-Mountain-Smoker-Accessory/dp/B01DE6NBTS/ref=sr_1_2_sspa?ie=UTF8&qid=1516658815&sr=8-2-spons&keywords=weber+water+pan+cover&psc=1and use a bolt to permanently attach it to underside of the lid, then use a thick stone like you recommend above.
I'm thinking that using your pac man charcoal set up I should be starting out with about as efficient a set up as I can get. And maybe I'll be making pies that are good on top and not torched on the bottom without abusing the world's supply of charcoal and firewood.
I am a little concerned about the wear and tear the really high heat will do to my performer bowl... but hey, if I wear it out, then I got my mileage out of it.
I'll replace the broken stone with a baking steel for when I make pizza in the house.
BTW, it took me a while to see your last post because I wasn't observant enough to see that there was a second pages of posts... lol