I don't think, FK-SA makes the curve... because, if I play against an opponent with FK-SA, they usually curve the ball too. My wife used around two seasons her playmaker for freekicks, and he was also able to curve it.
I only think, FK-SA leeds more often to goals, that's all.

Yeah... 1 1/2 season ago, I got a good player with CK. Last season, I used him on both sides, but at the half of the season, he only had 4 assists, so I set back my PM to cornerkicks... and he made incredible 23 assists in just half a season. He also kicks them, at current season, he had four assists and four times more it was shown the PM-icon, without an direct assist. I really love this guy.
Btw... my experience says: passing, crossing and creativity are the important attributes for PM. I also think, best position is MC or DMC.

If the foot matters is just mysterious... Nik has a thread, and he says/thinks, foot doesn't matter. For myself, I'm not sure. My AML/AMC/AMR is left footed and plays at AMR much better than any other position. If he scores, it's direct from the box after crossing, or like Arjen Robben... goes from the wing to the middle and shoots.