I am not a wheel builder, but have researched and had built several sets of hand built wheels. If you are set on Velocity A23's, don't do 24/28, especially for cross. It is kind of a whimpy rim. I have 32/32 A23's with Record hubs and double butted spokes (Revolution IIRC) and I am happy with them, but wouldn't use them for less spokes. Granted, I am large, so take it with a grain of salt.