Force feeding is very stressful to balls and should only be done when all other options have been exhausted and the health of the snake is in danger. These guys can go a long time without food with little ill effect, and force feeding a shy snake like balls can actually put them off their feed.
That said, if it is taking food unassisted now, GREAT! I wouldn't force feed again unless you start noticing a significant weight loss.
I wouldn't worry about a rat pinky being live when it goes down. Their teeth are practically nonexistant at that point.
I agree that the food is probably too small. You'll want to find something that is as big around as the widest part of your snake. Hatchlings usually go for rat pinks, or juvenile/hopper mice. In young balls the movement of a hopper mouse can entice a feeding response, but if it's taking rats you may want to try a rat chub/pup one with it's eyes still shut. Though you may have to wiggle it a little to get your ball to strike.
Hope this helps,
Allison