Think there are probably ~4-5 people who could be good moderators.

That's true.. Are there any disadvantages to having more mods?

Yes, am wondering this myself. - I had some comment that I wasn't active enough... which made me wonder whats the problem with having a few less active moderators (who do moderation once every few days). I don't really expect to find more time for moderation, but think its helpful none the less.

Yes! More slots, and have more advanced moderators kind of watch over the "under mods"