HELP WITH CABINET INCUBATOR!!!
The color choice make prefect sense now. If there is adequate air flow, there should be no need to split the heating elements top and bottom.
The GQF type coil heaters work well. They are only 225 watts . I think you could snip off a 1/2 of the compressed coil and bump the wattage up a little. I don't have much experience using light bulbs, but they may be a good choice in this application,being easier to adjusting the overall wattage .