So have been propelled into the two eldest sharing (5 and 3) because twins are arriving next year. We need them to share for at least 18 mths if not longer (dependent on house move or not), would you bother with a mid sleeper and youngest on the mattress on the floor underneath the mid sleeper or an ikea kura with the same config? Feels safer than bunks as eldest not up as high and much cheaper but will the smallest end up hating being on the floor? Anyone done this? Thanks