Ok so if you see a big mayfly hatch try this fly. It is a pheasant tail cripple. It was sold by Idylwild, but apparently they are not shipping flies at this time. It is kind of sad, but it appears Idylwild is on it's last leg. It is actually pretty easy to tie. 25+ fish on the Tenkara rod this last weekend on the East Carson. Multiple fish on the Upper Sac and the Stanislaus
I've fished that fly a lot and I can also vouch for its effectiveness. However, like you said it is really easy to tie and hard to mess up so I can't imagine they would sell a lot of them. This fly is very similar to the Quigley Cripple which is usually my go-to fly when there is a mayfly hatch.
You guys fish this on top exclusively or nymph it too? I tend to be hesitant to tie on a PT during a mayfly hatch cause I've always done better on alternative mayfly patterns and because PTs get thrown out there so much. But I feel like this could produce even fished slightly subsurface or on the bottom like a drowned may or cripple. Also I'm thinking rooster for the hackle?
Cripples are fished exclusively as a dry fly. In fact it is very hard to sink this fly. It was designed by Quigley to imitate a fly stuck in the shuck. That means it didn't quite make the transition from nymph to dun and is stuck on the surface. It is very effective as Quigley used to fish the very tough waters on the Fall River. I was never a big dry fly guy until I figured out that the Tenkara rod is very effective for dry fly fishing. You can actually lift the whole line off the water and skitter flies upstream and downstream it drives the fish crazy! I now carry a Tenkara rod in the back pocket of my vest in case I see fish rising on the river. A complete setup is about $200.
I've fished cripples for over 20 years and they certainly can be very effective. I have tied Quigley cripples, callibaetis cripples and even PMD cripples. The callibaetis cripple has been particularly effective for me. Most people feel that dry flies produce smaller fish while nymphs produce the bigger fish. Most often this is true. However, there are some lakes (Manzanita being one) where (for me) I've caught most of my bigger fish on dries. I've probably averaged more fish with nymphs, but their average size was not as big as those caught on dries. Last year I fished a private pond and the fish I caught on a callibaetis cripple averaged 16-17 inches while those caught on nymphs averaged more like 14-15. I caught way more fish on nymphs when the rises quit, but nothing over 17. I lost one fish on a cripple that was probably in the 22 inch range.