Vivarium Leaking

[Gocntry]

Wooden vivarium, and white bathroom sealant, which I was told was just fine providing you leave it 24+ hours.

The problem is that I can't see where the join is at the front of the viv, no visibility so I can't see what I'm doing.
Has anyone used any plastic sheeting at the bottom of the viv too?

Use a small hand mirror to see where you need to silicone??

I've used an inspection mirror to see into all kinds of goofy angles I couldn't fit my head into