I only make rectangle quilts. I use my quilts I make for our double size bed to fit as a bedspread. We have an 18" thick mattress. Roughly 85 x 95" I make pillow covers to cover bed pillows. I don't like the looks of the over the pillows. I make them 24 x 36". Like small quilts. I also make up my own quilts to suit me.
Very easy for me to see how a rectangle quilt should go on my bed.