is it more effficient to use lots of small point sprites or fewer but bigger ones. i want to make trails of dust from cars skidding. i know how to control the location of it, and give it some randomness of movement, but can i set things like the scale of the sprite, the opacity, and the color? or maybe even a tiny texture(8x8 or so)? also, are they automatically blilboarded with teh camera? that would save a LOT of calculations with lots of little dust sprites from the cars.