Wedi is a great and easy system for that configuration. The pan itself will be 36″ x 48″ so you will need to cut it down if your looking to have the end of curbs be at that dimension, otherwise it will come out 37 1/2″ x 49 1/2″ with the 2″ lean curb and 40″ x 52″ with the full 4 1/2″ wide curb
So weight of the glass will have no effect on either curb. Once the tile is installed with thinset…the curbs will be super solid.
I would suggest cutting the curbs on a chop saw and cut them at a 45 degree angle and then use the wedi sealant to join them together into the rabbit joint (sealant fully in rabbit joint too)
I personally like the thinner curb. If you use a solid surface top like marble or travertine, you can use a 4″ wide pieces rather than a wider 6 1/2″ piece with the full curb. So it really up to you on how you plan to finish it
Lately, I have been using schluter edging and tile. Hopefully you can see this one in the picture attached.
As for tiling it, it would be easier to cut the tile on a 45 and start at corner and work back to wall.
Easiest is a solid top though, but that is more of a style decision. This one is a full wedi curb with 6 1/2″ travertine solid curb tops
If you are not getting the glass custom ordered, I would recommend finding the glass enclosure you are going to install and make sure you configure the pan and curb placement to fit the enclosure properly.