A little double crossdraft gas kiln

[Jaguaretei]

Hi!   I plan to build a small gas kiln to start my first experiments in ceramics. 

I researched a bit, flipped through some books, and it seemed accessible to me to build a little double crossdraft kiln.

This model of kiln, known in Japanese as itte-koi-gama (いってこい窯) , is popular as a wood kiln (the Phoenix kiln or Philosopher’s Kiln) but little used on gas.

It looks like a plan for a small gas kiln was published on Building Your Own Kiln, Three Japanese Potters Give Advice And Instructions , but I didn't have access to this book.

So looking at some kilns over the internet (1, 2, 3, 4, 5)  I made a plan for a kiln  to firing in cone 10 for two 12X12 inch kiln shelves, the chamber is 3,1 ft³.

I wonder if anyone has ever had contact with such a gas kiln.

My main question is about the size of the chimney. The models I saw didn't have a big chimney, which leaves me wondering about Fred Olsen's rule.

What do you think? I was thinking of building a five-foot chimney. 

The input size corresponds to the output size and the size of the chimney tunnel. Is it better or safer to have a wider chimney or not?

 

Any comments that might help me in this kiln are welcome, thanks!