I breeder consolidating in my area has a large 9-bin rack for sale. but it is belly heat. I was gonna put my three big breeders in the top three then put their babies in smaller tubs that would fit inside of the big tub that goes with the rack.. I was told belly heat is bad for babies. It does have a Herpstat II with it...... what are your thoughts on belly heat and is there a place to go for easy to read instructions to make my own rack that doesn't require a rocket scientist to build.