A vote for porportional sizing
Most people would agree that a 23mm tire is appropriate for a single bike and 150 lb rider. Why would a 23mm or slightly larger 25mm tire be the best choice for a tandem with 355 lb bike-rider combo?
I vote for 28mm tires from your list. They will not slow you down and will protect you from bent rims and pinch flats. They do weigh more - maybe 200 grams for both tires with wire bead 28s (there are kevlar bead 28s available that are lighter). The 200 grams will increase you total weight from approx 161,170 grams to 161,370.
Just my opinion and many would disagree.
Wayne Sulak
2006 Co-Motion Speedster.