Setting relative display size of link coordinate frames?

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I'm currently on Gazebo 9 on Melodic and wonder if there's a way to simply increase the relative display size of the local coordinate frames, ideally on a per-object basis in the SDF file?

Makes a lot of sense for them to generally scale with the size of the object, as they do, but I want to use a small sphere as a pose target with a large, visually dominant coordinate frame.

Maybe it's simplest to manually add a RGB cylinder triad to the link visual, but curious if there is another built-in way.