skimmer setup question?

[kpc01]

I am trying to reposition my skimmer, it hasn't ever really skimmed well since I got it and I think its time to try something else. My question is where should my water level be in the skmmer? I am redoing the plumbing back to the sump and I need to figure out how tall I can go with it. What would be the ideal water level? A,B,C. or D

 

[chadfarmer]

D with the sedra turned off

 

[kpc01]

thanks, I'm going to move the skimmer around some and I think I am going to get the original needle wheel for the sedra...just in case its the mesh mod thats not helping me.