One more; as far as finding heavier ones, that has been the hard part with the malossi. Treats is supposed to be getting some soon but still waiting. Heaviest i've found available are some 6gr on e-bay.
At least ours are useable, those who get theirs from 50cc.nl will find that one is a slightly different part number, and comes with the red colorolls, which are only like 2.7gr, and solid-center.