The 10T single is made by winding ten turns of wire around each pole of the motor. A motor is usually (but not always) made with the thickest wire that will fit. A ten turn double is wound with two strands of wire wrapped ten times around each pole. The two strands are easier to fit, so the total thickness of the wire can be greater than wit a single strand. A triple or quad would have three or four strands of even thinner wire, which would be even easier to fit, so the total current carrying capability would again be even greater.
Single strand motors are lighter (less total weight of copper wire in there) so they feel "snappier" tending to accelerate and decelerate more quickly than multi strand motors (less rotating mass = less inertia) Multi strand mototrs will typically spool up a bit more slowly, but have higher top speeds. The best choice depends on the type of track. Ovals and open flowing road courses tend to favor multi strand motors, while tight technical layouts tend to favor singles.
As long as the number of turns is greater than the lower limit of the speed control you'll be fine.