....Just a few thoughts about October Caddis:

In Montana, if you are not fishing streamers in October you're probably chasing Blue Winged Olives. That's what generally provides the best fishing. There are always a few big October caddis around. But never more than a few scattered individuals.

On big tailwater rivers especially (Big Horn, Missouri, etc) many fishermen use an indicator of some kind, because it's almost always cloudy and windy at that time of year, which makes following tiny flies nearly impossible. That indicator might be an ugly hunk of yarn or foam. Or it might be a Royal Wulff, grasshopper or October caddis. The indicator fly typically takes no more than 2-3 fish all day long (which is 2-3 fish better than an ugly blob of foam). But a big bushy indicator fly in the middle of a Blue Winged Olive hatch seldom produces a lot of fish.

Fishing an October caddis as the primary fly in October probably isn't a high-success strategy.