I bought a "big board" about a year ago. (Not the largest one, but it is longer than normal fabric is wide.) It sits on top of my regular ironing board, and can be set aside to iron clothing if needed.
I found that I can set the big board so that the bottom of my original ironing board sticks out at least a foot at the right end. (Left end for leftys.) That's plenty of room for the iron. If you want to put the starch bottle, scissors and a pin cushion there also, you need to make allowances for the cord. A hook from the ceiling would be ideal but I'm not there yet.