Today I finish the shower trim and try sealing it with flex seal. Still have to install the LEDs and do a waterproof test. I'll update on how well this holds up (especially if it doesn't).

Previous shower install videos:
Installing the shower:    • Installing a Shower in the Short Bus  
Trying to fix it with trim:    • I Messed Up - Trying to Fix Gaps With...  

Flexseal: https://amzn.to/3KL2ddG