Get as big a piece of granite as your oven will hold and what the temperature up full whack. Whilst this does make a slight difference, it’s nowhere near as good as using it in a gas bbq with a lid. Effectively a full on pizza oven minus the wood fired bit.
Use it in one of them with foil lining the bottom of the stone (to avoid direct heating), turn the bbq up full and you’ll get it hot enough for authentic pizza. I do the dough in a bread maker and put it in the bbq/pizza oven with a £5 pizza peel (big paddle you see being used in pizzerias, available from catering stores or eBay).
Dead easy and works a treat.