I choose to use RBI's reptile cages and find that the 2x3x1 is perfect for an 700g+ ball python. I have three of my girls in three cages now (they are all over 1000g) and will add my next three biggest to three more cages (cages that my boas are outgrowing!)
My ball pythons in the cages have never had a problem with the space and those cages actually result in LESS upkeep than the tubs. Love my cages!!!!