Early design questions for igloo style oven

[@ngeLCD]

I’m in the early design phase of a 42” “igloo” style oven and am looking for some tips on dome design. I’d like the finished exterior of the dome to be tile or thin stone adhered to the dome with thinset. I saw a great video on YouTube of a similar build and the builder installed tile over a 4” layer of vermiculite which was installed over a layer of insulating blanket. Is there any issue with the stability of vermiculite that is installed over a soft substrate (blanket)? Or is it preferable to have a physical break between the inner dome bricks and the finish layer to avoid thermal cycling from damaging the exterior? Regardless, what is the best dome “sandwich” for an igloo style oven?

[ogopogodude]

Hello, ..I am a newbie to pizza oven world. But I am 75% done my igloo / dome style pizza oven. I pretty much copied a design from a youtube build. You may want to youtube search THIS: Lee McNeil pizza oven. There are three parts to this video youtube build. I also went to the website called "sketch up" ... and downloaded a real cool 3-D design which was also uploaded by this Lee McNeil dude. I built a smoker oven that sits beside, but is associated with the pizza oven build. I will upload my photos soon. I am currently modifying my build as my mason needs to make a vent behind the antique cast iron swing-open door.
I have yet to build the outer cosmetic dome over the fire-brick dome. This means I am at the stage of also insulating the firebrick dome, but haven't done so, yet.

[ogopogodude]

Here's a few more photos of my build. I even included a photo of me standing on my dome, ... trying to figure out the hole that i was going to drill thru the masonry to make a vertical venting upwards (behind the door) ... my mason said he wants to cut out the door and then re-position it forward (outwards) and then make the vent .... I have made two "curing" fires ... and there is certainly soot / smoke coming out the door and this needs to go vertically upwards using a vent behind the door.
This was my first mistake ( faux - pas ) that I am going to correct. But the way, .. I am making the vent go 45 degrees backwards and then upwards once it is vented over the centre of the dome ... as this looks way more cosmetically appealing .. in my opinion.

[ogopogodude]

[ogopogodude]

[ogopogodude]

WooHoo ..!!! My trustworthy mason came today and made a vertical vent ... but not before cutting out the already- masoned cast iron door and moving it forward. Now, I will have a (pretty much) smoke -free fire start up situation ... so I won't smell like I have been camping when I start my pizza oven. Plus, .. when I use my smoker fire-box that is down and to the left of my dome, ... the smoke can go upwards and then smoke whatever I want smoked (salmon, or beef, .. or even beef jerky , etc) and then the smoke won't come billowing out the cast iron door area, .. but instead rise up thru the vent after it has completely intoxicated the inside of the dome with smoke ..... Here's a few update photos: