If my Brinsea is full, there's no room. I recall someone explaining how they taped it display side up in the lid, but I didn't try that, yet. If it's not full, I pull a rack and just lay one or two on the floor of the incubator.
I had room to put mine on the egg turner after a little rearranging in the empty spaces.
But I can barely read it through the plastic. I have to aim a flashlight in there and get it just right.
I was just thinking today that I wished I had looked for a temp/humidity gauge that had a probe I could drop down through the vent hole.
Next time.