Alan Scott Oven dimensions

Hi

I'm looking for advice

I'm about to start building the 32 x 38 inch Alan Scott oven (same as in the Bread Builder's book).  I'd like to make it about 12 inches longer.   Can anyone see a problem?  I was going to keep the same dome height, dome:door ratio and width.    I've read the Bread Builder's chapter on the ideal oven dimensions but length doesn't seem to be mentioned. 

Cheers

SourdoughNZ