Runtime of some functions

Hey I am making a mobile game and I really need to make it efficient.
What is faster, 2 Box colliders for a flat sphere or one sphere collider? Of course the spherecollider would be slightly better, but if the runtime is much higher I would use the 2 boxes.
Also I am checking if my character is walled and I need the side where the wall is. (collisionpoint.normal is unreliable) Currently I am using 4 boxcolliders at each side of the character, but I also could use 16 LineCasts, which should work slightly better. (The colliders call OnTriggerExit when moving from one wall object to another which the linecasts wouldnt do)
Maybe I will post more questions in this thread. Or is there a site where the runtime of the functions is listed? Thanks for your help.

 

I agree with this.
If your performance is impacted by such a small difference (two box colliders vs 1 sphere collider), there is a much bigger issue.

 

Thank you for your answers. It turns out, that I could implement everything I needed without caring much about performance, and the game runs smoothly on the target phone galaxy s2.