Size and shape

[BlackpoollBaker]

Weather is warming and I’ve begun laying concrete blocks for a bas. It will be 120cmx120cm I’ll be putting Thermolite blocks on their side as insulation under the firebricks. Dome will be formed over sand cast in refractory mortar. A 6” flue already purchased but need help on best size to fit on my base.would be appreciated

[UtahBeehiver]

If you refer to the Forno Bravo plans, section 12. Recommended maximum oven ID is 36" for a 6" ID flue.