@NathanielStenzel you can optimize with trace width or trace routing too… some folks have done that. Personally I prefer to just put a sheet of aluminum on top of the heater and be done with it.
@Ryan_Carlyle A heat spreader helps you with hot/cold spots on the surface, but it won’t save you from a current bottleneck that can act as a fuse.
Fyi KiCads python scripting is awesome and can do all the traces for you. That’s how I did the traces on the clock I’m building. I built a script that did the layout for 30 leds in a circle, then matched the caps, then did the traces. Like magic.
A little bit of python coding and you can have a custom module that you just enter in the wattage and size and it does all the magic.
Spiral both lines to the center, and join them there.
http://baxsie.com/images/CFA10051/CFA-10051_0v0_PCB_Preview.pdf
The spreadsheet I used: for calculations.
http://baxsie.com/images/CFA10051/PCB_heater_trace_width_calculations.xls