You may find that the STC-1000 controller has too wide a temperature control range Jon.
Yes, I think Chris is right here - you may find you get too much temperature variation for a good hatch. However, I had a cheapo incubator when I first started that just turned a lightbulb on and off, and it worked ok to be fair.
Speaking with my control engineer's head on (I'm still at work
), I'd either be looking at some sort of analogue heat control, or pulsing like Chris says, or wiring the lightbulbs individually to give a stepped heat output (perhaps driven by a small PLC?).
You might as well give it a go for this hatch though and see what happens. I'll be interested to hear how you get on
.