Vela - Shower Single Fixed Panel 34" - 60" Installation Guide 

Only silicone the outside of the glass. You don't seal both sides. If water finds a way to get in there, it's a perfect place for mold to start growing. Only seal the outside.

Could just use 3m double sided tape instead of drilling into tile and shower base

But what if the shower floor is sloping?

Is it ok to drill through the water proofing for the floor bracket?

Can you install without backing behind the wall anchors? I have 1/2 inch travertine, 1/4 inch thinset, 1/2 inch float, 1/2 inch drywall. So only 1/4 inch max is gonna grab into the stud behind the wall? Are the green anchors enough?