The README.md appears to be out of date in regard to number of servos supported, it says:
"The VarSpeedServo.h Arduino library allows the use of up to 8 servos moving asynchronously (because it uses interrupts). In addition, you can set the speed of a move, optionally wait (block) until the servo move is complete, and create sequences of moves that run asynchronously."
and VarSpeedServo.cpp says:
"Timers are seized as needed in groups of 12 servos - 24 servos use two timers, 48 servos will use four."
The README.md appears to be out of date in regard to number of servos supported, it says: "The VarSpeedServo.h Arduino library allows the use of up to 8 servos moving asynchronously (because it uses interrupts). In addition, you can set the speed of a move, optionally wait (block) until the servo move is complete, and create sequences of moves that run asynchronously."
and VarSpeedServo.cpp says: "Timers are seized as needed in groups of 12 servos - 24 servos use two timers, 48 servos will use four."