Just to add something different to the discussion:

Up until the past few weeks, when the sun came out and reminded the bass that bigger is better, I was catching them with some regularity on a #16 elk hair caddis, of all things.

I was after the 'gills, so I'd cast parallel to shore and retrieve across the surface very slowly and steadily. After a while, if no gills came up, the fly would dip under, so on a whim I just kept up the extremely slow retrieve. When it got within sight, if there were any followers, I'd just stop it, and more often than not I'd see a big old bucketmouth vacuum it up.