This is a pretty simple fix, depending on how demanding your audience is...luckily I had some great instruction from my client.
Step 1: Nubbin Prep
I drilled two roughly perpendicular offset holes and inserted toothpicks in them. I trimmed the toothpicks so as to provide a solid foundation for the Sugru to grab on to.
Step 2: Prosthesis Attachment
If you don't like fingerprint marks in your Sugru, I have found that keeping your fingers moving across the surface keeps them at bay. The ridges in the claw were made with a knife blade.
I opted for a lobster-esque monster hand...it was met with a smile and apparently passed inspection...