it depends on the spacing used between the glass. there are vinyl sweeps that slide onto the edge of the glass similar to the one that should have been used along the bottom and actually top. problem with these are that they take away from the 'frameless' look even thought they are clear plastic. how long has it been since you had this installed? Here is a link that might be useful: vinyl sweep

Ours was 3K, included all parts, glass, labor. The shower is a modified square shape a square with a slice off of one of the corners. Of course, that's where the door is. He really struggled with getting it all to line up. Mostly because the standard door wasn't the same size as the opening for it and there is an additional trim piece of glass beside the door. Looks great in the end, fainted at the price. Good to see that others are familiar with these kind of numbers. He did everything, measure, fabricate, deliver, install. They were very tall pieces of 3/8" tempered glass. It was no picnic for him!

is the tile already installed? If not , you can leave channels/rabets/dado for the glass to sit into. You can also just have a very close fit and it probably won't be too bad. Steam is dense so it's not going to rush out of a small crack at the joints, it will escape so it depends on the rest of your design as to whether you can work with this. The weather stripping looks horrible and kinda defeats the purpose of frameless IMHO. Glass guys offer standard advice: frameless and steam showers aren't good company. It can be done, but you really need to design and refine all the details from the outset. Sounds like maybe you waited too long to involve the glass people or the steam generator was an addition.

I'm not an expert in transoms or steam shower design, but I'm surprised nobody has yet said why they were invented, get installed, and are used. 1/ Steam machines make steam. More and more of it. Without new steam, the experience of a steam shower can be less and less enjoyable. New steam is needed. It actually puts pressure on the walls, and in 24hour commercial steam showers this is a big thing. But, even at home, where does all the water vapor go? It doesn't all become liquid (condensation) and go into the drain. 2/ :: Plan where it will go, otherwise it will go places you don't want it to go. A transom is a safety valve putting your excess steam into the bathroom, from where the fan exhausts it. 3/ :: Otherwise steam seeps into everything. Wall-ceiling junctions. Light fixtures. Into the attic insulation. Water vapor can penetrate anything, because it has time on its side, and the world's best solvent: H2O molecules. The opposite approach is "If you only use the steam shower for a short time and not often, who cares?" Anyone want to defend that point of view? I think there is no point building something that you "really ought not to let run". Some future user might want long steam showers, or frequent steam showers. Without a transom, you are guaranteeing that your escape route for water vapor will be confused, since it's unplanned, uncoordinated and unwanted, and your result will eventually lead to problems. As far as I know. Anyone reading this thread so far would be well advised to look more into it instead of concluding that transoms are just for fun. Many homeowners don't care much about codes or practices and will allow anyone to build anything for them. After that, it may or may not work as expected, and ultimately the homeowner may or may not be satisfied. This applied to all fields of construction. My writing this out is not to say that anyone here has been intending to do the wrong thing deliberately. Hth