Hi,
you will need to fiddle with the physics settings A LOT, so don't give up, it is possible. You will find few problems down the road.
you can't go to fast, else, your ball will go trhough colliders, if that's the case, you need to limit the ball speed and increase physics calulation steps to cover for that.
Have a look at the the marble game by m2h, I ported it in playmaker, and is a good start to start increasing the pace of the ball.
https://hutonggames.fogbugz.com/default.asp?W936bye,
Jean