Thanks, GM. The fixture just has two crimps holding the globe in place, no screws. If replacement globes would fit that is what I'd prefer, but if I could find some plastic sheeting I could make into a cone that would work also.
I like the idea of self-tapping machine screws, and if I break the current globe getting it out I guess it doesn't matter. I'd like to preserve the fixture itself, though, since so far I have spent money only on some A. nana "petite." Everything else I already had.
My husband put aluminum foil around the whole globe and that "works" to aim the light into the bowl and keep you from being blinded looking at the bulb, but it somehow lacks the esthetic mood I'm going for...
He does not understand why I am so eager to fix this, but once I get an idea in my head there is no stopping until I have the problem solved.
I plan on putting a "tequila sunrise" guppy in there, since the bathroom has a yellow theme and it will contrast nicely with what I hope to be a green bowl.
I am keeping a photo diary of the process, and this is in the gallery in my sig.