I have a gradient ambient air temp in my glass tanks but I also have the ventilation kind of set up like my Pro-Line HDPE cage is where there is a slight gap on the cool side and the CHE is on the hot side with about a 1" gap around the dome so the cool air settles in on the cool side, flows over to the warm side and rises up where the CHE is and the escape is regulated by the air gap around the dome. I personally am still trying to figure out how Boaphile cages create air circulation as they are vented around the door, the tops are completely sealed so I would imagine air would get stagnant in them but that's a different topic.
As to the OP, I wouldn't worry about getting it exactly perfect. As long as you get it close. I mean in nature they aren't living in a 90F perfect environment. Heck when I was a kid, I had a ball python that I used a 55 gallon tank with a screen top and heat lamps and his humidity was only room humidity and he used to have horrible sheds but you know what, that gal went from a hatchling to an over 4' female and ate all the time and was fat as a cow. They are pretty hardy and a lot people seem to think they are fragile like fine china. the only thing is you got to regulate belly heat as burns will mess them up which is why I don't use belly heat for any of snakes. Think I have used belly heat once for my pied girl and then I dumped it as I use aspen and the belly heat did squat with 2" aspen.