I did another safelight test this morning. First, I used a CD as Ken spells out to check for other colors of light. With the vanes wide open, and the Yellow tape filter in place in the bottom, the Red tape filter in the vanes, I saw no color except yellow. Still with the vanes wide open, I exposed two pieces of paper to the safelight, one was flashed before the safelight exposure, the other afterwards. Both showed signs of fog after 3 minutes in the flashed area, none in the borders. Both showed fogging at 7 minutes in the flashed area, none in the borders. My previous test was done in a different darkroom and I cannot guarantee there wasn't a light leak.
I expect better performance with the vanes fully or partially closed.