If I choose to make my own snake rack, what would be the best way to use fexwatt heat tape?

1. What size should I use, and what watt should I use? 3" flexwatt with 6 watts, 3" flexwatt with 10 watts, 4 inch flexwatt, 11 inch flexwatt?

2. How should I cut it? Should I cut single peices of it, and put down a seperate cut of the flexwatt for each shelf? If I do this, is there a way to wire all of them together so that I only need 1 plug? Or will I need to wire them all seperately and plug them all in seperate into an outlet?

3. A few people have told me to run it throughout each shelf. How is this done? From side to side, or front to back? How will I run it from one shelf to the next?

4. What is better, belly heat or back heat? I know belly heat will help with digestion, but so many people use back heat now, it seams like many are switching to it.

5. Anything else I need to know? I just want to make sure I understand EVERYTHING about flexwatt heat tape before I go burning my house down or putting a snakes life in danger.

Thank you