Yeah, I've got that page open and had a bit of a read of it.

I've looked at quite a few designs now and there's almost an even split between the resistor camp and the thermistor camp. There are certainly benefits to using resistors but I don't like the failure modes much. With a thermistor if the relay fails to close at least the resistance should drop to a fairly low level, with the resistor you're always pumping out the full power until, hopefully, the resistor goes open circuit. That strikes me as a bad design. The thermal fuse isn't really a solution either as it probably won't operate fast enough to prevent serious overheating.

This is essentially why I'm seriously considering just using a thermistor and living with the waste heat. All the disconnecting designs just move the potential fault somewhere else and if you want the design to fail safe you have to design for the possibility the resistors / thermistor will be taking the full load.