Wiring flexwatt

What gauge wire are you using to connect your flexwatt? I tested the temperature on each level of my rack and it seems like I am not getting enough current to the last level to heat it up to the same as the first.

Heat rises, your top temps will never match your bottom temps. My middle is set at 89, my bottom level is 85 and my top is 92. Nothing to worry about.

I pre-wired some more, and laid it on the flow. Each piece reads different temperature.