How much leeway is there in ERD? I'm pretty sure now the rim is a Velocity Aerohead OC, but if I wanted something else is it just a matter of how much or little thread is exposed on the spoke?

It is a rear, so I know I'm getting into fragile weight weenie territory with the 24 spokes. As for the seller, he is sending the hub and spokes with an original cracked rim used as protection. So I guess I'll get my answer. I don't quite understand how he came to have a cracked rim AND a new one that is used with a Powertap.

Now all I need is a matching front...