Dear Zak,
Welcome to join our group. Thanks for making the glass tray and turning it into reality.
I have some design ideas, I may show you picture next time.
For the PDMS layer material, let me give you some handling precaution as quoted from this thread:
Effects on fertility:
Test Type: Two-generation reproduction toxicity study
Species: Rat, male and female
Application Route: inhalation (vapor)
Symptoms: Effects on fertility.
Remarks: Based on test data
Please wear productive gear, avoid using torch to vaporize the PDMS.