Wing forwards usually tend to move to the middle, especially when crosses are made (check the last match of the 1st on the ranking!). So, playing with, for example, a FR and a MR might a good idea if the MR is able to go to the line & cross. If that happens, the FR should then move into the middle when the cross is about to be done. Also, wing forwards move to the center of the area when a cross is made on the other side and MR’s don’t do that so easily!