Ditto what was said earlier, cept I haven't worried about the number of tails either. But maybe i should. I don't know. I honestly Don't think that makes a whole lot of difference.
But most of the time I'll use caddis patterns anyway. The predominant hatches where I fish are usually caddis, and there always seems to be at least a few caddis hatching, even during a mayfly hatch. Sometimes using something a little different can trigger a hit.
With caddis, it's really just size and color (body and wing color). But like the rest of us, I also carry tons of other flies.
With caddis, I sometimes tie some without hackle so they sink down into the film more.
A guy who used to be a regular here years back (Jeff F) gave me a couple of wool wing caddis. No hacle. Just dubbing and a wool wing. They do work as an emerging caddis, and I think the wool helps reduce the numbers of misses because it gets hung up in the trout's teeth. Just a feeling.
then there are soft hackles, and other caddis wets. I'm not very good at fishing those, but they do work.