Very good! The 4321 is a more offensive 451. I don't know if you're using 3 MC +1 AMR+1 AML or ML+MC+MR + 2 AMC.
I used the second schema when I was at levels 5,6.
Now I'm a 14 level player,I could rarely use this tactics against strong defenders and midfielders.

From level 8 ,good teams are mainly built on good defense and midfield,helped by a good striker (I have only 3 ST in my team...but I'm beating also 15 and 16 level teams that play with many AM and ST)