QTR-Quadtone RIP

I've been creating transparencies with a dot/grain pattern in them.
I've been using the "1440x1440 super" transparency setting, but I was
wonder how this is different than the other two 1440 resolutions
("1440" and I can't remember the name of the other one). Would these
change the size of the droplets, or . . . ?

Any info or details would be helpful. 

Thanks, David.