Biggest reason for a top loader is my age and bending down that low to load the kiln as the location has a low shed roof. If I made it a front loader, I'd have to make it a car kiln.
My first kiln was similar with a fiber top 3 layer tied with kanthal wire, this one will be a bit smaller only about 30-34 in deep. I need a quick turn around/test kiln. if I need a quick 20 or 30 mugs and a few other things, I can turn it around load and fire in a day.
I have some 1 in high alumina 28x13 used shelves that are bowed, I could cut length wise and prop along side the flame channel(stack side) as a thin bag wall to protect the ware if needed.
Mark are those 3" or 4" folds by how wide, 12 inches. How do you overlap the courses to keep the courses tight enough to keep all the heat in?