-background turning off command
<Settings>background=none</Settings>
This is used in: Gamma Ray Bursts.xml
-trials turning off command
I don't have a toggle command, but you could set trailsegments to zero.
<Settings>trailsegments=0</Settings>
Trailsegments is used in: Spacecraft - Cassini & Earth in 1999.xml
I'll add a trail toggle XML support in version 2.
-body drawn i normal size command
I don't think I've added support for this to the XML files. I've added this to the list for the next version though.