Racks are great if you have a large collection, but to be honest (and this is only opinion, not a scientific fact!) if you only have a few snakes I think Pituophis especially are better kept in larger enclosures. They are such active snakes that they really seem to benefit from the extra room.
I only keep a few snakes these days so I can allow them this luxury which many others cannot. It's up to you at the end of the day though!