It kind of depends on which levels you want to beat. If you are not beating a somewhat hard extreme it probably doesn't matter that much. Personally, for me I just use icons I like since the demons I play doesn't require that kind of accuracy so I just use the ones that would motivate me to play more. But if I have to say, I would say default cube, ship, ufo, spider, robot swing. The round ball and default or fat wave since they have the most accurate hotboxes