I finally got the resin working right in these. I managed to get some disposable graduated mixing cups from my dad, and when I scrupulously measured each part, it cured properly.
I tried very hard to make the suspended doo-dads within the resin match the background. I particularly like the small mirror and the piece of transistor. The background of the small mirror is a wrapper from candy my husband and I bought as a souvenir while touring the Alhambra.