The fans on my 5108 have had an additional controller added to allow them to run for a period of time after the exposure, to help the bulbs cool down, I can vary the time. So I can't see a problem running the fan continuously, just double check it's voltage.

I have a heavy duty transformer that was used for spotlights and have kept it as a backup, it would be fine for B&W but not stabilised enough for colour.

Heads differ so I can't tell you how to get at your filters but it's easy on my 10x8.

Ian