I'd recommend a wood-fire with no gas assist, then. In the gas assist, the fire is more of a visual thing, with the gas maintaining a more steady deck temperature. If you were primarily doing oven-roasted meats and seafood, this would be your best bet. But, for pizza, you can cook in these ovens anywhere from 550 to 750 F and achieve good results. Also, lots of flame is required for the initial rise and also for browning of the crust.
Mise en place for your oven for authentic Napoli-style pizza would be: whole logs (white oak) to be placed in the oven at the end of the night to keep the deck from cooling too much overnight. Quartered logs are used to start the fire again in the morning and bring the deck up to temp (minimum 525 F to cook pizza). For cooking, you need to split your wood down to about 1"x1". It can be a pain to do this (you need 3-4 milk-crates full of wood chopped like this on a busy night), but you need wood that will create a lot of flame without adding too much to the coal bed; the deck temp can get out of control if you're not careful. Even so, we had busy nights where we had to pull the whole coal bed out of the oven and restart the fire in the middle of service. :eek: Also, dry wood chips are used when you load the oven with pizzas; they give you a quick, big flame for the initial rise of the crust.
As far as costs are concerned, gas and wood cost about the same to run, wood being nominally more expensive due to the labor involved if you want to do it right. Then, of course, things might even out again considering that a wood-fire oven never needs repairs!