All right, I posted some Info above, which was untested and promised to come back after testing. I DID testing...a LOT of testing....but I never saw any changes, no matter what settings I put in.
Now comes the clue: I accidentially stumbled across
THIS THREAD!
There is the Problem: I'm using an ATI 9800 Pro...so none of my settings show up. Looking at the target ring as displayed on an NVidia card I assume that all my assumptions considering the settings of the variables are actually right, I just won't see any effect of it.
I just hope they get this fixed for all supported graphics accelerators soon....