will too many perfer moves cancel each other out?

i mean, I wanna make a striker attempting more curling shots, but while at the same time he also got other perferred moves such as "lob the keeper" and "place shot". as a result, i rarely seen him trying curling shots, he attempted far more "place shots" instead.

in order to get him trying more curling shots, should i ask him to untrained the place shots?

Don't know but there's one way to find out.

What might happen is the game won't explicitly tell you but he'll automatically reject because some part of the code designates conflicting PPMs and prevents them from being combined.

You can curl a placed shot though

As isuckatfm said, it's unlikely you'll find any PPMs that will conflict with each other now so you need to analyse your players attributes and see what suits his game best.

Curls ball is most useful for Try Long Shots more than anything i think, when a striker is 1 on 1, you want him to Lob, Go Around The Keeper or Place A Shot. Curling the finish at close range isn't really useful but it can happen.