All of the stuff is at the upholsterer's place right now, to which I don't have easy access. I did talk to him a minute ago and he explained that the covers for the backs were inches shorter than they need to be, and the covers for the seats did not reach the backs.
I've got a call in to Legendary to see if they would know if the Dart seat cores would be the same dimensionally as the Valiant seat cores. Waiting for them to get back to me...