We are looking at buying a king mattress set. My husband is about 300 lbs so we don't want something that will break down but he also he likes the softness of plush or ultra plush. We purchased a Westin Heavenly Bed about 10 years ago and I love that it produced much less motion than another bed we have had. I had to put a big down feather bed on top of the pillow top so it was soft enough. Paying the current price for the heavenly and then adding a $300 topper isn't in our budget. I am considering buying a firm king set and then adding the big cushy costco foam top. We don't know what the best firm set is to hold up a big man. Can you offer some suggestions to get something good that doesn't transfer motion, is firm enough to hold up a big man and cheap enough to add a $300 cushy top?