Agreed, 8-bit data, 16-bit address (but 12-bit program counters) is massive for relays! That's a lot of relays to do anything. But it turns out their start was

Agreed, 8-bit data, 16-bit address (but 12-bit program counters) is massive for relays! That's a lot of relays to do anything. But it turns out their start was when they stumbled on 1500 relays in good condition. So they were set in relays from the start and could aim "rather" big. They do have a lot of relays.