Going back to the back-to-back seating idea, whilst it certainly increases the capacity of the train, that doesn't necessarily translate to a higher throughput.
By doubling the number of seats, you're doubling the number of people who need to enter and exit the station. Wing coasters are a faff to load and unload at the best of times; imagining 24 people trying to leave and 24 people trying to enter (of which, many will be kids/families) just sounds like a colossal nightmare.
Realistically, whilst back-to-back seats would increase capacity and a theoretical throughput, I don't think it would have a significant impact on an actual throughput.