Installing Frameless Shower Screens

Did your contractor use the U-channel aka glazing channel for your wall-to-glass installation? Was this done during the wet works, or after the bathroom tiles are all completed? Or did your contractor use wall brackets to hold the frameless glass panels?

I am asking because I have seen some pictures whereby the U-channel is exposed and it's so ugly. My thoughts are that if the bathroom is completely renovated, then there is the opportunity to hack the wall, and recess/conceal the U-channel.

But for completed bathrooms, or bathrooms that are only going through minor touches, then contractors should NOT use U channels but wall brackets instead. I am personally very against the use of silicon because of bacterial growth over time, from the constant contact with water. It'll look so grouty over time, and I'd have to change it all by myself when my DH is out stationed. (yucks)

My children's shower pan is not a regular shape (quadrant) and I am wondering how my contractor can join the glass panels without the use of silicon. Any suggestions? Installing a stainless support bar on top of the shower screen is out of the question. This is the bathroom where I am only installing the shower screen, and all else remain.

Look forward to the experts' advice.