If my elemetary physics hasnt gone the way of my maths knowledge, then your motors are producing 4.1A of current (nominal/continuous)

Err-ing on the side of caution by saying that the stall current will be four times this amount (16.4A) then a 25A Sabretooth should do the job easily, even taking into account stall currents larger than 16.4A but I dont see that happening with 24V 100W scooter motors