Awesome, lets say I go with the one from Reptile basic's. It's only got 1 probe, would I just place it in a middle rack, and just know the bottom ones a few degrees cooler. Then the tops a few degrees hotter?
I did think about building one, but like you said it can lack the professional appearance. Not that I'm gonna have a bunch of people seeing it, I just like to be proud of what I got.
I set mines at the top. And i get like a 2 deg differential throughout my rack.
My top one is at like 90-91 bottom sits at around 89-90