I've just added a few of columns to the worksheet customization tool so you can see all the suggestions in this thread played out in real numbers:
I added power potential, step change in power potential, total change in power potential, and plowthrough index.
The starting spec input boxes will display starting power and plowthrough after you add your first tape locations.
The power is for the center of the racquet and the plowthrough for the center (about 21 inches from the butt end) and for a groundstroke of incoming ball speed of 30 mph and racquet tip speed of 65 mph.
BE SURE TO CHECK ALL THE UNITS INPUT RADIO BUTTONS TO MATCH YOUR INPUT NUMBERS OR YOU WILL GET CRAZY RESULTS.