Sancho is a Spanish name and it means Saint. In slang it means the other man, a guy a girl is cheating with. Sancho means sancho in English as well as Spanish. Pearl Yamada.
The general rule of thumb for a horizontal smoker is that the firebox should be 1/3 the size (volume) of the cooking chamber. These are just guidelines based on years building smokers but your mileage may vary! Cooker Chamber Type & Size.
A good firewood box is large enough to hold at least one day's fuel, and it also holds enough different sizes of wood for the different stages of the fire--smaller pieces for starting the fire, larger pieces for building it and the largest logs for maintaining it.