Jack E might be able to report what he did, but if you read Woods book, there is a section where Woods talked about the correct proportion of front to back. So to stay true to that proportion, rather than an 8' front and 8' back, that should be 6' front and 10' back for a 16' building.
Height at the peak of the monitor would normally then be 10' too. Basically, build it as intended for the 10' x 16' building, but only 8' wide.
The correct proportion for an 8' wide building is 12 deep. Technically, 7 1/2" wide x 12' deep. (No plans in Wood's book for an 8' x 12'.......I made my own plans).
Either way, what you will find with this building when the side windows are shut, is dead calm air back at the roost level. When I went out this evening to close the pop door and do a head count, wind was blowing straight in to the open end.......about 20 mph. So strong it was a real struggle to close the door from the inside. You could hear the wind outside howling. Yet inside, with the door closed, all was calm. So wide open ventilation (basically a covered run enclosed on three sides) and draft free at the roost level.