what about the silicone?

Will the silicone be enough of a seal? If so I would love to avoid the channel thanks.

You can use a u-channel and there are several really wonderful examples of showers that have been installed with them. TreasureTheDay's stands out as a recent example.

But you can also use clips and it will be just fine. We installed a steam shower about two months ago with a set up very similar to yours (fan outside) and used clips with silicone sealing the space between the glass and solid surface. Though it's been hot, we've used the steam shower at least once a week -- it's great for aching muscles after a day of gardening!

Your glass installer is quite right that no residential steam shower enclosure is perfectly steam-tight. But even with our transom, we have minimal leakage. It is not a problem.

It's tough to get far enough back to get a picture + glare from lights, but here's ours.

Thank you so much, it's all so very helpful. Wow, your shower is really lovely. Great to hear you're enjoying the steam aspects in the summer as well. Can you tell me - on your shower curb - is that paint or tile under the solid surface? Thanks again.

Thanks for the kind comments about the shower. As to the short space below the curb top, it is the same tile that's on the shower walls. I had wanted to just continue the floor tile, but got outvoted by both DH and the tile guy. In the end, I think it looks fine. But I also think it would have been ok to continue the floor tile (either the larger 36x6 version on the bathroom floor or the 3x3 version on the shower floor).

we can guarantee no leakage where U-channel is placed and one of the most cost effective installation & best applies when your door is hinged off the wall. but clipped system is typically used when your door is hinged off a panel and a header is not desired

Here is a link that might be useful: Bathroom remodeling