We have two Big Agnes bags that zip together. Mine is long and her is regular length but we sleep even - head and shoulders. Our BA bags have no bottom insulation and rely entirely on the air mattress, which slide into sleeves, for ground insulation. Both bags are designed to be used separately as well as zipped together so no need for a separate sleeping system for couples. A plus to the BA design is you can’t roll off (be pushed off) the mattresses in the middle of the night.