So today I am putting a down payment on a baby BRB that I will pick up at the reptile super show in Pomona this coming January [insert excited squeals here]. I have a basic understanding on the husbandry 90+ humidity for a baby and temps in the mid 70's-low 80's. I'm gonna put the plan for my set up, and I would like some suggestions on things that I am lacking or things that should be changed.

-I have a 15 quart sterilite tub (I plan on a PVC cage once the little one gets bigger).
-I'm going to buy a basic black hide box for a hot side hide, and I'm going to make a humid hide with a tupperware container and sphagnum moss.
-I'm going to use a heat pad of course with a thermostat (I would appreciate any tips on a baseline to set it at to reach a good temperature though).
-Obviously I'll have my digital thermometer/hydrometer and monitor surface temps with a temp gun (I use that system already for my bp's).
-I'll have a bowl deep enough to soak in opposite the hot side.
-I'm still not sure what I should use for my substrate though (I'm thinking a cocoa husk/cypress mixture).