I would Say
5'W x7'L x 7' ceiling

Inside size 5 x7 x7

Always wanted to build some, mostly to keep out the cold....never did get roundtoit.... but the easiest blind I had was the parked in the back work truck, electric windows, weather tight, radio and heat if necessary!... had deer walk right along side it....

What kind of stove is that 330?

I built 2 in a 100 year old barn. 8x8, 6 inch insulated walls, internet, TV. I built it about 18 years ago, no way I could do it now. It was a scary build, the top floor is 30 feet in the air. But at 69 it's fun to turn on the heat and snipe a coyote.
The red bulb doesn't mess up your night vision. We have had a lot of fun hunting with night vision and thermals out of them.