The bog standard "uprated" fan switch will be fine, actually better as the hysteresis is much smaller, personally I would never chance the temp by switching manually, as you say only need to forget once and it could be a expensive mistake, but I do have a warning light for my fan/s.
I have put a blue led in the top left corner of the rev counter to come on with the fans, just gives a bit of reassurance, and looks pretty too, should have used a pink flashing one!!
tabetha