The hard part of setting the focal point measurment is, where is the "Look Point" on your dish? Fortunately it's not as critical a setting as in C-Band dishes.
From Chapparals web site I used this chart as a guide.Magic Static,
Since you own a 6' WSI Special dish like me , how deep into the scalar ring did you located the LNB. My LNBF is of a different brand (DMX-741), but maybe that would not make much of a difference.
My setup is working OK, but maybe it needs some modification and improvement for better reception and performance.
Thank You.