Ok....that guy is just barbequing a steak, the fire I make is at least 4X what that guy used, much much hotter, the oven floor would be 750F and the steak would be charcoal in 8 minutes. That explains the moving the fire around to heat the oven....its probably more efficient like that but I promise you the taste of the food is very different. When its HOT, the sugars caramelize and you get a flavor that you really can't duplicate any other way and it doesn't matter what you're cooking, it will taste different than anything you've had, I promise. Olive on everything not bread too, it just seals the flavor in when it hits the heat.
Next time you guys fire up the oven and you thing its ready, throw a couple more pieces and send me a pic....and I'll tell you add more wood.
Get the oven HOT, dome burned clean and the floor to at least 600-650, 750 would be better. As I said, I know its wasteful...but man is it good.
As for building, it pretty important the floor is well insulated. the door insulation helps it stay hot for roasts or bread if you do that stuff, but the floor insulation is critical to even heat.
Have you found this forum? Some useful stuff, but also a few guys that post alot of BS.....lots of oven builds to look at though
https://community.fornobravo.com/mine is here
https://community.fornobravo.com/forum/good-background-information/brick-oven-photos/408068-will-an-oven-fit-looks-like-yes-pa-build