ITSF Garlando balls are like ping-pong balls filled with a little bit of weight, and a little grippier on the outside. Imagine a plastic coating around the cork ball and you can picture what it would be like. They are lighter than any north american ball.
For the mirco games ball, maybe try the bonzini ITSF ball. It is not cork, and although I'm not sure what the weight is that would be a decent option.