Best SA for the top scorer challenge

I'm a new player and this is my first season. I'm leading the league and have a top scorer but only 1 point and 1 goal ahead of the second place, so I'd like to improve not to lose the lead.
My top scorer is ST/AMR on the AMR position, he has FK SA, and now I want to give the second one. The Corner specialist is good, but not for the top scorer, so the choice is between Shadow ST and 1-on-1... Which will be the most efficient?

Also, what will be the best formation and tactics against low level opponents (~50-70% vs my 90%, often inactive or NPC) to optimize the scoring of the certain player. Normally I use 4-2-3w-1 or 4-2-2w-2 with the AMR in focus, sometimes 3-1-2-3w-1 but even if I get a big win (4:0 or 5:0), the goals are distributed evenly between all AMs, and my top scorer gets +1 or +2, while the opponent (the guy on the 2nd place) has a weaker team but often manages to get +3 for his top scorer, so the lead is disappearing rapidly...

The last game was 6:0 with AML (3 goals), AMC (1), ST (1), and AMR (1)... 5 goals (including AMR) were scored in the first half with Focus passing: mixed. I tried switching to focus right flank, and they almost stopped scoring. :(

Well, if play him as AM often more than ST then, SS is the best choice, CK also good, FK+CK combo is good.

and for tactic and fomation, just play with your best squad, do not change your tactic too much as the game nowdays is so random, stay with one, change when you need to, like when you defeated and need to comeback etc etc,