I have been considering buying a sofa or sectional with a bench cushion (Taylor King Gramercy). As I usually lie down on the sofa I think this is a good option. My concern is that eventually the cushion will will dip and form to where weight is usually applied. I know rotating and flipping the cushion will help prevent some of this but is there a particular cushion construction I should be considering for a bench cushion to help maintain its shape? Are there any other concerns I should take into account for a single cushion as opposed to multiple cushion seating?

Thanks - Ed