Just saw this in another post, by lee676:

"If a 23w CFL is too big, the Philips A21 LED 75w equivalent wouldn't fit since it's larger than the smallest 100w equivalent CFLs (23w). Sylvania and Philips both sell "micro mini" 23w CFLs that are the same size as a standard (A19) 100w incandescent bulb. The Sylvania gives off better light quality IMO, but also is a bit dim when first turned on; the Philips starts at nearly full brightness but gives off slightly pinkish light. Sylvania also has a "Living Spaces" CFL whose light quality is an acquired taste that I haven't acquired. "

Very helpful. I hadn't considered the size of the A21. I can contact the MFR for dimensions. That said, the micro-mini Sylvania is much cheaper, gives off more light, and I don't think I'd mind the delay to full brightness as long as it is dimmable.

I do have one more of these lights (already mounted). It takes a 60 Watt candle base. Is there an LED light I can use in this one, as well? I can provide dimensions with this one.