They sell industrial strength light bulbs that are used in things like shop work lights, etc. They work fine.
If you use the two bulb setup, you also have one for a backup if the first bulb goes out.
Hot water around the outside will also free the box. If you notice in the pics, I do have small slits to vent the box so the slightly larger one will not hurt anything. I would leave it closed however unless needed to change the bulb.