Greg,
At best its a Carling Black Label idea!
Most people prefer to cast SH's that are about 30' long. Shorter and they dump and longer are awkward to handle.
Most rods are designed to false cast 50' (or so) of line.
If you have a 9 wt rod and a 9wt Int. full line, you need a 10 or 11 wt SH (maybe even a 12).
If you cut 30' off the 9 wt line to make a SH, it is suitable for use on a 6-7-8 wt rod.
I guess Rocky could always buy another rod.