I make rice cereal treats days ahead so they can settle. Mash them down to compress. Then I brush them with white chocolate and it seals them. I don't use butter and I don't put them in the fridge because they gather moisture and when they come out the sweat and get sticky. But for turrets on my castles I use paper towel rolls and ice cream cones. I have also made the treats and poured melted chocolate coating into them and modeled with that.