I use a layer of batting and one layer of the silver fabric for ironing boards. I like to use 3/8 inch plywood instead of 1/4 inch.
I just use straight pins to hold the fabric on and don’t staple the fabric. Another good size is 18x18 to iron small projects by the machine. You can add a layer of the cabinet shelf cushion product on the back to keep the board from slipping. The cushion backing will hold the pins in place.