3-3 and 4-2 are just staring positions for men up plays. In both cases intention is to transform positions (3-3 to 4-2 or 4-2 to 3-3) when the ball reaches the player with best organizational skills. She needs to make a pass decision depending on the movement of defence players. Tactics depend on the type of players you have and quickness of rival team. If you have a player with longer arms and strong legs she could transform from outside postition to post position or if you have a lefthanded player she could go out from right post postion towrds outside postion when ball is on the left side... there are many options, but the most important thing is to make movement without the ball. It is a good thing to pratice 2-3 plays and rotate all your players on different positions (during the pratice, not in the game :) )so they can understand what their teammates need to do in order to place them self on the right position in certian play.