Opportunity is missed by most people because it is dressed in overalls and looks like work. - Thomas Edison
Ah, the old bug light story, eh? It's been over 4 years since I had a bug light in operation. My suggestion is just coat your screens under florescent light and let dry in the dark like a drying cabinet or a covered screen rack. When it's time to prepare one, just pull out a screen under normal room lighting, tape on the film and expose. The only story I ever heard of room lighting exposing was turning on the light behind a washout sink before wetting the screen had a negative effect. Mine are florescent behind my washout sink so must have been some robust suckers. I work under normal room (florescent) light and stay away from old man sun. You can't run fast enough to shade to stop the sun from exposing. Well maybe if you were Superman.
The only story I ever heard of room lighting exposing was turning on the light behind a washout sink before wetting the screen had a negative effect.
When I worked out of my garage my pressure washed blew up so I had no water in my washout unit. I had a job that I had to get done so I just grabbed the screen and ran outside in a shaded spot to wash it out with the hose and I got nothing. It would not wash out anything. I could see the design for about 15 seconds then that even went away. I figured out if i took a spray bottle and wet the screen really good let it sit for about 30 seconds I could get outside and wash it out with out to much trouble. (so glad I don't have to do that again) I use Aquasol HV. Its great stuff but you have to have your times right. 25 seconds on my photo sharp exposure unit with 10% OEM.