If by saying 'sorry', you're congratulating me on being right, then thank you, it does feel pretty great finally having my ideas on this subject being fully vindicated
Seriously, though, Antoine/Mitch, you do know that the indisputable success of the draft door thoroughly proves everything I've been saying, right? What is the draft door other than an extremely low throat? My calculations were obviously a bit off in terms of the necessary height of the throat opening required to reveal a tangible difference, and, for that, I might need to nibble on a corner of my fedora
but my theory that a lower door shortens pre-heat times and saves wood is, thanks to the draft door, no longer a theory, but proven fact.
It's quite simple, the opening in the throat prototype was too large to produce a discernible difference. The draft door proves that it needs to be smaller. Now, the total size of the opening in the draft door, when visualized as a single hole, isn't viable to work through as a throat, obviously, but you can certainly split the difference between the prototype and the draft and end up with time/energy savings and an opening that will allow the necessary access.
A prototype throat opening reduction of half the size should be perfect. I don't think it's a coincidence that what I'm describing is pretty close to the opening size of a Stefano Ferrara. I hate to sound like a broken record here, but the Italian oven builders have been doing this thing for quite some time and seem, for the most part, to know what they're doing. I think it also reveals that door sizing, as Jeff (shuboyje) and Tom have pointed out on more than one occasion, is about more than just arbitrarily picking a height of 63% and expecting it to be perfect. A particular oven might perform better with a higher or (in this case) lower door, and you can't avoid taking the shape of the opening into account as well.
Rather than looking at doors just from a perspective of the ratio of their height to the height of the dome, I think it might be prudent to look at doors the same way we look at chimneys by calculating the total surface area of the opening. This would take shape into account a bit better and give us a much better idea of proper door sizing than the, imo, far oversimplified 63% figure.