Depends on a lot of things. Normally, I use 2D when I know I have a cube to throw after, to guarantee a true blockstring, or a frame trap. From far away, blue cube, fire cube, or wind cube. But When you're close up and the cube doesn't have to go as far, you can do the big cube, or lightning cube, to frametrap. But if you try to do those when you're far away you can get mashed on. In general, just try not to give them any frames to jump out, cause that is likely the way you're getting punished the most often.
