just sharing a little tool I've made along the way on my current project. Got fed up trying to mirror across primitive selections and whatnot, so here's a little wrangle to mirror across the pose_scope attribute. It does rely on a consistently named set of controls and the suffix/prefix stuff needs to match the existing pose_scope attribute, but I've found it has sped things up a lot.
Hope someone finds it useful
EDIT: ok, little initial fixes. Now no group is required, it tests for existing prim attrib and also for prefix matching, pose scope attributes with a matching prefix will get mirrored. Also an axis parm