This is a close up of the inside of the chair back.
I can't tell you how much muslin that I used for the first chair. Maybe I can figure it out on the next one. Whew - it took the whole weekend, one day of which I didn't even get out of my nightie! I tore the strips from tea-dyed muslin.
The cotton sheeting is actually a better bargain as it is 108" wide!!!