Double oven in wall

Hi,

Any thoughts re my current project please.

I want to install a double built-in oven into a 600mm thick cob wall.

I am proposing buying the oven and then constructing a carcase to suit. The carcase would need to be approx 600x880mm. (I can do a good job of this !)
I will then get a builder to make a hole in the wall with lintels etc. and install the carcase.
For simplicity, I think we will probably go right through the cob wall and then make good on the 'other side'.

As this finished...

Double oven in wall