Question About Cooler incubator size...

OK i decided to breed my pair of balls this year and my House snakes are close to breeding size so now so...

I need incubator...

I'm going to build chest cooler one but I have question about size...

For this year if She lay I'm gonna have on clutch of ball eggs and Probably 4-6 clutches of house snakes (about 4-10 small colubrid eggs per clutch)

I'm looking on Coleman Extreme series.. because they look spacious and have drain so i can move cords from fan and Heat Tape...

My Question 50 QT or 70 QT with one will be better....

I have no Idea of eggs container sizing...

50 QT have Interior Dimensions: 20.5 in. x 8.75 in. x 12.25 in.

How many egg boxes i can put there ??

Anyone ???

What do the colubrid eggs require for incubation? I know a lot of colubrid eggs are different than balls. But if you only have one clutch and don't plan on expanding just get the smallest one, it will save on electric and easier to control temp/humidity.