what size dome lamp. My new 4'x2'x18" showcase cage should be arriving tomorrow. I've decided to go with a ceramic heat emitter and was wondering if anyone has an idea what power would be best. The room the enclosure will be in is fairly warm and the temp is pretty constant, I will be using a thermostat. I'm thinking 100W should be enough and 150W will be too much, am I correct? The other part of the question is the dome lamp for the CHE. Should I get a 10" or 8.5"? Does a wider diameter spread the heat more and a smaller diameter less? Thanks?