Door width = 1/2 hearth width?

Hi all,

A general enough question I thought it merited its own thread, as opposed to continuing off my other thread.  Mods, I deign to your judgment, of course.

So, in the interest of just getting going, I plan on putting together a mud oven, hearth dimensions tbd.

In the book Build Your Own Hearth Oven, they give a suggested door width of 1/2*hearth width; if the hearth is 22.5" wide, that would mean a door of 10.5" 

That seems really small to me.  I intend on bread baking almost entirely, with the occasional pizza.  The peel I use to off-load boules is itself 12" wide - wider than the above door.  

FWIW, this is just an entry-level oven, to get one up and running.  I only intend on a loaf or two, and if all goes well, will plan for a larger oven.  Just to learn the build and baking dynamics.  Likely, as suggested in the book, 22.5 wide or 10 bricks side-by-side (i.e., 2.25", or 10 bricks side by side for the width, and 2.5 bricks @ 9" end-to-end for the hearth length).  

If I go by the books' suggestion on the door width, I would need a bigger oven.  But I don't want a larger oven with just a loaf or two, as I know a full oven is a better oven. 

So - how do you guys calculate the door width?

Edit:  While here, might as well ask on firebrick sources.  With overage, I'll be looking at only 30-35 bricks.  I plan on medium duty, with layer underneath TBD.  Can anyone recommend their good source for direct purchase, and what specific bricks they went with?

Many thanks for your thoughts.

Paul