The client decal prefs I know of are:
$pref::Decal::decalTimeout = "5000";
$pref::Decal::maxNumDecals = "256";
$pref::decalsOn = "0";
Though I'm pretty sure they're mostly for the bullet holes and footprints. I'm not sure if you're able to disable the markings on armors and such since they're tied to an animation, but it's worth a shot - you might even try modifying the damage textures. Somebody who has had to disable them before may be able to help more.
Comments
$pref::Decal::decalTimeout = "5000";
$pref::Decal::maxNumDecals = "256";
$pref::decalsOn = "0";
Though I'm pretty sure they're mostly for the bullet holes and footprints. I'm not sure if you're able to disable the markings on armors and such since they're tied to an animation, but it's worth a shot - you might even try modifying the damage textures. Somebody who has had to disable them before may be able to help more.