First ensure that RX1 AF is at 100%, VAC TX and RX gain is set at 0dB, and that you've set up some sort of virtual audio cable software in accordance with my VAC tutorial. Make the appropriate configurations of the virtual audio cable software (Voicemeeter Banana if you follow my tutorial).
Here are the two relevant setup tabs in Winwarbler. You can see in the first one I'm using Voicemeeter Banana and have selected the left audio channel.

In the second setup screen I've selected RTTY-R, as this will cause the correct selection of DIGU modeif you are effecting PowerSDR control via DX Commander, which I am. I dropped the stock waterfall gain to "3" and the FFT average is raise to "2". Those were the only changes I made to the defaults.

The resulting audio levels were actually too high. I had to drop VAC RX gain to -10dB.
Here is the result. Note that I carefully adjusted the squelch control towards the left end of the scale and my Vert Height to 2.0.
