The 500-tx is same size as 800-T. Add the 550-T to the 700-T listing as it's the same size. Possibly the 500-T also, but for some reason it looks smaller, than the 550-T/700-T.
Actually with the S.S. units, most of them have the speaker connectioin at the lower edge of the back panel and with a chassis that overhangs a little, it's easier to get to the spkr connections and you don't bend the "Y" spade connectors to get them on. .