Howdy again Vx3man,
Since I've only run this test one time, I'm a little hesitant to hang my hat on it, but here goes, Dropping my Discrimination from 90 to 30 only changed my signal loss from 38 to 30. On the other hand, dropping the Rx from 10 to 4 changed the Signal loss (sensitivity probe) from 38% to 14%. If you feel the need to lower the Signal loss: hit the Rx first, and hit it hard if necessary. It will lower the Signal loss, reducing the Dx won't be as effective.
There are a lot of posts out there that say the "power" of the V detectors is in Dx, NOT Rx. As a generalization, I drop an inch of "depth" (air test) for every 10 points that I drop Discrimination.
I'm a newbe at this, but for now, I'd lower the Rx to 6 if that's what it takes to get the Signal loss down to the 30 +/- range, and I'd keep the Dx as high as possible.
Dave