Okay, I took your advice, and it's all been quite helpful. No oranges or balls happened to be handy, so I used G.projector. I adjusted some problematically-shaped plates and got a general sense of proper relative direction. I also studied this diagram for some time: File:Tectonic plates boundaries detailed-en.svg - Wikipedia, the free encyclopedia

I came up with this. Red arrows show plate motion and the other arrows show boundaries (purple: divergent, blue: convergent, green: transform). Am I getting closer?

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