Jeff, I'm interested to hear what you think of the vent.
My oven has a Neapolitan vent, and with the oven down to the brick I could have easily tore it out. I didn't. It works, in fact it works well, but I don't feel I've seen any magical properties from it a standard vent designed well cannot provide.
For a while I've felt a lot of the properties the Neapolitans link to the vent could be directly related to lack of insulation. Heat travels from hot to cold, always. The bigger the difference in temperature the better the heat transfer from hot to cold. IF you had a poorly insulated oven that is leaking heat out the top of the dome, and you placed a Neapolitan vent on it, you would essentially insulate a large portion of the dome. I'll try to explain. Imagine you have two poorly insulated ovens. Oven A has a standard vent. Oven B has a Neapolitan vent. Let's say the brick at the top of the dome in both ovens is 1200F and the "insulation" is 200F. You have 1000F temperature difference. Lots of heat will leak out of the oven as it moves from hot to cold. That is Oven A. Oven B has a Neapolitan vent, and because of that it has a large portion of it's dome covered by hot Flu gases instead of "insulation". Let's say those flu gases at 800F. You now have 400F temperature difference driving the leakage instead of 1000F. You will lose less heat out of the dome and as a result burn less wood, and the oven will get hotter. Those are the exact things they claim a Neapolitan vent achieves.
In a well insulated oven the Neapolitan vent leads to a large uninsulated area, more complicated build, and more restriction to airflow for what gain? Potentially slightly higher draw in a hot oven roaring for sub 60 second bakes. I have no problem being a guinea pig, but at this point I don't recommend them for home ovens.