I don't want to risk raising a hot discussion here, but an easy way to avoid all of this is just to get rid of the condensers entirely and go with a cold light. I bought a wonderful old D2 on eBay for about $150, got a gorgeous cold light for another $100, and could not possibly be happier with what I have. No need to change anything for different formats except lenses and you have the advantages of cold light printing, stable light output, little or no color change, etc.