First of all I want to thank you for the valuable feedback info and for pointing some issues with our manual and specs. I will correct them a.s.a.p., but for now I can tell you that this oven is based on a general-purpose traditional Brazilian design and that's why the vent is smaller, it does help with heat retention. There's no problem in enlarging it but I have to check with the production engineer what is the minimum wall thickness that should be left around the vent. I will add that information to the manual eventually.
The temperature (wrongly) stated is actually for cooking bread, pizza should really be somewhat hotter. Some recommend up to 900F but anything over 700F should be fine.
As to the tall flames hitting the ovens walls, it's all a matter of thermal shock. Any brick or mortar oven should be heated slowly and evenly to avoid cracking, but after it's hot, no problem. For the same reason it should be left to cool by itself. I will revise the text to make that clearer.
The bricks are fused to the oven floor during production (that helps to keep our production costs competitive) but if needed a further layer of thin bricks can later be laid on the floor, for the oven is tall enough for that.
Our ovens are not made by Artmill.
Depending on demand, there will be larger and smaller models available, as well as Brazilian barbecue grills. We can offer stainless steel and cast aluminum and iron doors, with or without glass viewing ports.
We are now producing a video showing oven installation and operation, with relevant demonstrations (including vent flow) and operation tips.
Thanks again for the feedback and please fell free to point out any issues with our materials and products, your opinion is invaluable to help us develop a better product.