I would say that if you are setting up the 32 Qt tubs to go in width wise then you are going to want to have heat on one end with 11 inch flex watt for that shelf.

For a rack 48 inches high using 32 qt tubs you will be able to go 6 tubs high.

I have not seen your plans for the rack but you said you want to also use 1 shelf for 2 15 qt tubs, if this is so you are going to want to use 3 inch flex watt running all the way across the back of the rack for your belly heat on that shelf. Now this is the way I would set it up but I am sure you can go with back heat, so there are several options to go with. You just have to go with what works for you. There are alot of DIY Racks out there so do your homework and see what works for you.


Richard