Use a local Xresources override

roles/home-gui/files/Xresources

@@ -1,3 +1,6 @@
+! Use 96 (100%), 120 (125%), 144 (150%), 168 (175%), or 192 (200%).
+Xft.dpi: 96
+
 *color: true
 Emwm*activeBackground: #c0c0c0
 Emwm*activeForeground: #202020
@@ -12,7 +15,6 @@ XClock*minuteColor: #c0c0c0
 XClock*render: true
 XClock*secondColor: red
 XClock*update: 1
-Xft.dpi: 100
 Xft.hintstyle: hintfull
 Xft.rgba: none
 xterm*activeIcon: false

roles/home-gui/files/xsession-freebsd

@@ -1,6 +1,10 @@
 #!/bin/sh
 . $HOME/.profile
 xrdb -load $HOME/.Xresources
+if test -r $HOME/.Xresources.local
+then
+    xrdb -override $HOME/.Xresources.local
+fi
 xsetroot -solid '#101010'
 backlight 10
 mixer vol.mute=1