Mini fridge incubator issue...

I found an old mini fridge on craigslist that didn't work for $20, and I'm setting it up as an incubator. My boyfriend cut off all of the cooling stuff in the back/bottom. Now I need to figure out how to rig it up. I have some flexwatt heat tape that is already wired I could use, but I think it would be easier to use some extra zoo med heat cable I have. This will be used with a Ranco t-stat. (I'm expecting 3 clutches, possibly 4 if another normal I just got ends up female...right now I have already paired up BumblebeeXNormal, PastelXNormal and AlbinoXNormal) After getting a few 6 qt tubs and putting them inside to see how they fit...well that's the problem, they fit...but it's tight. The fridge has a separate freezer section on top which will hold one 6 qt tub, but I don't want to have to heat that up also unless I have to. The heat needs to be on the back of the fridge ideally, but I'm afraid the heat will be too close to the tubs that way. What should I do? Put the heat on top of the fridge instead so its farther away? I'm planning on getting a computer fan put on the inside too, will the tubs be okay temp-wise if I have a fan? Or should I just chalk it up as a loss and find a bigger one?

I´ve put heat on both sides in a small sodacooler and attached a fan in the middle of the top in the cooler so the air will circulate.
I´ve got the exact temp in the whole inqubator but it´s only made for 2-3 clutches.

I have a full sized fridge bator and my flexwatt runs right down the middle on the back it works fine there but in a mini fridge? idk I might go with the heat cable from zoomed instead just cuz it wont be right against the containers. or you could use deli cups with single eggs instead of shoeboxes for the entire clutch lol