Replacement heated bed for Emaker Huxley

It's no secret to owners of Emaker Huxleys that the heated bed has a design flaw. Many owners, including myself, have experience multiple failures of the heated bed.
http://www.emakershop.com/forum?vasthtmlaction=viewtopic&t=276

IMHO, it's not if but when the bed will fail. I decided to design my own replacement bed for the Emaker Huxleys despite already ordering the ReprapPro Huxley's PCB bed.

Reason being that the PCB bed is not a drop-in replacement for the Emaker Huxleys. Changes to the Y-axis is required and the thermistor tables are different too.

This bed is designed to be a drop-in replacement and has a larger build area that will allow actual printing of the promised 140mm x 140mm area.

One of the problem when coming up with the design is determining the resistor to use. Indeed there seems to be no guide to this. For my case, I used my rusty electronics knowledge and some guesswork.

First, determine the power wattage for the bed. 90-100W seems like a safe bet,