Len and his crew have put so many of those things on they can do it in the time it takes for you to browse the shelves in the off season.
..and that is why if I ever decide to go with a ZE again then I would probably just take my bow down to Len's have him set it up for me. I feel confident that I could do it myself without any problems but I know Len can probably put them together in his sleep. You should see the "drawers" of components for the ZE that he has in his shop. It is shocking.