Would buying a sheet of foam and cutting to fit work as well as these? Could do with a good few of them and this would seem a cheaper option, was looking at this site http://www.efoam.co.uk/foamsheets.php?gclid=COjA8b2NzLQCFQ7LtAodyxUAKA and thought either the packaging foam sheet or high firm foam sheet would work like those wintec half pad things you see. Might be a very silly question, sorry if so!