The point wasn't that for any regular old shifter you need a super high gear and a super low gear. It was that by adding another CIM motor to each side, you don't see any major benefit until upwards towards 16-17+ ft/s, and any speed below 5-6 ft/s. I got this information from JVN's acceleration calculator. You can see by testing multiple ratios that between the speeds of 8 ft/s and 12 ft/s there is almost no noticeable difference in acceleration at all between 4 and 6 CIM drives (even between 13-15 ft/s the change isn't large enough to be too noticeable, though it is mathematically larger than the change found in the 8-12 ft/s range). This "magic window" holds some of the most favored speeds in FRC unfortunately, which is why I suggested a really low gear and a really high gear to fully take advantage of the extra CIMs. If the shifter was a 4-CIM, then 10 ft/s is a wonderful low speed since you're getting everything you can out of your motors.