Does anyone have kuhl roll-out nests with the removable one piece plastic bottom? Would like to know how the plastic bottom is constructed, and maybe see a side view of the bottoms because I would like to convert a regular nest to roll-out. Kuhl says that they are for replacement or for conversion, but when I asked them they said they were for kuhl nests only. It looks like they might be able to fit into an existing nest making it a roll-out.