In my experience, and this is just in my house--in the 6 yrs that we have had this house, it is a constant battle to keep the benches cleaned off enough for anyone to sit on. I don't plan to put this feature in my next house. One less place for clutter to collect.

I have 3 cubbies/open lockers. Each cubby is 20" deep and 24" wide. More than adequate for adults or children.

It sounds like you're getting there.

Thanks @red! Sounds like your bench is 6 feet wide? If it were clean (haha) how many people could realistically put their shoes on at the same time? :)

A commonly used width for space for a seated person is 24". Whether or not the ends are closed in this is still a pretty good estimate - seating two people side by side, even on a standalone bench starts feeling tight if you go down below 42" (or 21" per person).

Yes. But, most people when sitting, are sitting still with feet on the floor. Not the case, when putting on shoes. I'd add another 6" to each adjacent seat. If you only need 2 people at one time, 60" ought to be plenty. If there will be 3 benches, and 3 all at once, then maybe only 84" (I would think the space might get used like urinals---rarely 2 side-by-side unless alternating ones are full...)