Honestly, as long as the snake is happy and healthy, what it looks like is up to you.
I love the glass look as well, and I will not use plastic tubs. I got my snakes to look at and enjoy, and a tub would not work for me (I too am not a breeder, so space isn't a concern at this moment).
Where I am, the humidity in the air can be anywhere from 30-80% on ANY given day. I have a mini humidifier set up beside the tank (which my partner already had before the snakes) for the low humidity days. I think he got it for $20 at Wal-Mart or something.
The type of substrate you use also has an effect on the humidity. I use aspen, which can dry things out - so if you are super concerned, try something else... no idea what, as I too would like to know this info!Perhaps Reptibark or coco fiber/husk? Don't quote me on that though.
You can try misting before and after work, and see where the humidity sits.
Another thing you can try is putting a shed box in the tank at all times. A shed box is essentially a container/hide filled with dampened sphagnum moss. It works great! Only problem is when your snake loves it so much it doesn't want to come out when you want it too... *my corn snake specifically*.
Also, you could try having two water dishes in the tank on either side. If there is one over the warm spot, the water will evaporate into the air more. You would probably need to cover part of the lid for this to work properly though.
On that note, if you don't want to put towels over part of the mesh lid, I'm sure there are other things you could use to cover it - just look around some more, or get creative!
There are so many tips and ideas out there that I wouldn't worry if you have your heart set on a glass vive.
I hope I didn't ramble too much, I just got super inspired.
Best of luck!