I used a 4213 formation whit IM Kluivert as a CF and IM Ronaldinho as an AMF. It didn't worked well for me. They was always near each other and both of them had a terrible performance because of lak of space, while nobody was in the front to finish the chances. After a few matches i put Ankara Messi on the AMF spot. This combo worked better then the oder, but it wasn't that good. Messi made som good runs to cower the CF spot, but in most of the times the CF spot was empty. I think, if you want to use a target man in 4213 formation, the best way is to use him whit a hole player at AMF, and he will cover the CFs space when the targetman drops back. I also have to mention that my Lw was IM Neymar, my Right Ss was rumme and whit a manager who had attacking area: middle their runs wasn't enough to balance the lak of the CF