If you are stringing one piece, there are several ways to measure the shortside string, but here's one that is simple and a real time saver. Determine which end of the racquet the mains will start at. Start the shortside string measuring by putting one string through the center grommets on the long side from the opposite end that the pattern calls for. If the pattern says to start at the head, feed the string through at the throat. If the pattern has 16 mains, pull through 9 lengths of the head. This is eight lengths for the short side mains and 1 extra to reach the tension head on the last main.
Now feed the string back through the grommets for the first shortside main and pull the 9 lengths through. Now set up your clamps and away you go.This not only accurately measures the short side string, it also saves feeding the long side string through the center pair of grommets on that side. You may find the extra length of string on the short side isn't needed on strings that have a lot of stretch or frames that have shorter outside mains.