Skagit Short lines were designed for use with switch rods.
I'm not a big fan of the switch lines. They don't cast Spey style well when throwing tips and heavier flies.
The general rule for head and tip length is that the combined length is 2.5 to 3 times the rod length. A Skagit Short head (20 ft) and a tip (10 feet) is 30 feet. That is well within the norm.