OK. I played one game today in league using 451V and I won. I used the same formation 451V and same players.
One winger scored a goal, another one assisted one and the ST made it, so three attackers all contributed something important. in terms of the rating, the winger assisted one goal was 8, other 2s are 7.
I will keep using this formation, not only because this is the best combination I can have at this point, but also because I do not have other options. I have a descent team, but the embarrassing thing is that I only have one good ST, which was trained to 7 star, one winger 7 star, another winger close to 7 star - this is my attacking group. other than this, I do not have other good combinations, as I tested others, they don't work well. I cannot simply change 451V to 4141flat because my wingers are AMC/AML/AMR, so this is another reason I have to stick with 451V.
If I can get a very good ST, then I might be able to try narrow diamond, because one of my best wingers is not that stable. Anyway, I am still testing my team, and the formation; and I realized that if you want to use 451V, the key is the front 3 guys, they must be good, very good, which is not always true; if I can have another better ST or winger, I will be more confident.