Good question Rinussie, I don't see a real explanation for that so I just run it as is when I run it. All options are in the file but no good explanation as to how manipulation is actually done. Just tells what to run for what effect, not how to actually do that.
For example:
<!-- Type = Inertia / LinearRegression / LockToWorldHorizon / LockToCockpit -->
That line appears to be simply a notation, giving you options that you can take (denoted by the beginning <!-- and ending -->
So then in these lines:
<Filter Name="PitchFilter" Type="Inertia" Min="0" Val="0.99" Glance="0.4" Offset="-2" />
<Filter Name="RollFilter" Type="Inertia" Min="10" Val="0.90" Glance="0.75" Offset="0" />
Maybe you exchange Type="Inertia" to Type="LockToWorldHorizon"
Just guessing from memory, however I haven't messed with it yet.
*edit again. Maybe I'm imagining all this but I like Type=LockToCockpit for both filters.