Thanks for all your ideas so far.
Love Butyl, the swiss army knife of sealants, and wrapping individual wires then compressing the bundle seems like a good idea.
I looked at the Scanstrut pass through and it wasn't clear that it could waterproof a bundle unless the wires were individually passed through, am I correct about that?
The 180 degree solution triggered the idea for me to use a small clamshell vent. I would need one a little bigger than this one
and the edge is pretty close to the top, but I might be able to make it work.
And whatever I do it occurs to me to be sure to create a downward loop so the water drips down rather than wicking inside.
Still problem solving, but getting closer!