I did a few weekends of work on this (summer 2014), which were successful and indicated ways to improve. Most importantly, I uploaded some pictures of this work!

In particular, I made my mold smaller than necessary; it was tricky to remove the epoxied part. I also need to find a better epoxy that is both easy to mix in tiny amounts, and hardens well. I did not try using any mold release agents, though a coworker gave me some. I probably will try this in the future, but I suspect I'll get greater improvements by modifying my aluminum mold slightly (more tapers, for example).

I am also thinking I will do an attempt with just hot glue. I suspect this will work, but due to softness, the tiny soldered connections will eventually break.