What are your plans for a thermostat. The dimmers will control how much heat the lights put out, but they wont respond to outside temperature fluctuations. I think you wll find it very hard to control the temps using just a dimmer switch.
You will also need some sort of bowl, cup, plastic dish, or similar to hold water for humidity.
You may want a false bottom made out of hardware cloth - but its not a necessity. You place your bowl of water under there & they humidity is controlled but the chicks cant get to it when they hatch.
I'm trying to build mine on the same principal - but with a device to turn the eggs w/o opening the lid. Again- not a necessity but makes it easier on me.
Well i don't plan on buying a thermostat because the temperature fluctuation in the room will be at a minimum, there won't be a great change inside the incubator.
It looks really good as it is - I'm playing around with the wattage of mine now - I started out too low.
Also consider - if you don't have a way to turn the eggs w/o opening the lid then you will need to get in there 2 or 3 times a day for the first 2 +- weeks. This will let the heat out - which shouldn't be that big a deal as hens take a stroll every now & then too. But the humidity may take some time to build back up & humidity I'm learning can have a big impact on the hatch.