Disable RGBA antialiasing for fonts smaller than a certain size

Question

I am trying to disable RGBA antialiasing selectively for fonts smaller than, say 8 points, in GNOME 3.22 on Fedora 25. The general antialiasing is RGBA. I have tried placing the following in ~/.config/fontconfig/fonts.conf and /etc/fonts/local.conf but it does not work:-

<?xml version="1.0"?><!DOCTYPE fontconfig SYSTEM "fonts.dtd">
<fontconfig>
  <match target="font">
    <test compare="less_eq" name="size" qual="any">
      <double>8</double>
    </test>
    <edit mode="assign" name="rgba">
      <const>none</const>
    </edit>
  </match>
  <match target="font">
    <test compare="less_eq" name="pixelsize" qual="any">
      <double>11</double>
    </test>
    <edit mode="assign" name="rgba">
      <const>none</const>
    </edit>
  </match>
</fontconfig>

(I have both size and pixelsize because I copied it from a KDE configuration where it was that way.) Is there a way to do this?