Smaller "active corners" sensitivity

Is there a way to either add a "delay" for the activation of hot corner activity, or make it MUCH smaller (like maybe 2x2 pixels). If I run a Windows VM in Parallels (5.0.9310, revision 546799) in "full screen mode", then maximize a window, trying to close that window by clicking the "X" in the upper right corner becomes a huge fight between windows and the "corner flip animation".

I use all four hot corners in Parallels, so I can't really move away from the upper right. I just want a way for that "trigger" to be only when the mouse is in the VERY corner, not 20 pixels or more away from the corner.

Steve