That is a big key point Delopez. I've caught carp in 7 states, and every single fishery was notably different. While a lot of flies will work in a lot of places (carp can and do eat just about anything) there really is no magic fly for all locations. That said...there is probably a magic or go to fly for your location. You just have to figure out the main forage and go from there in my opinion. Out here, I catch about 80% of my carp on this:
I think the worm tail is often taken for the extended foot of a clam. I caught this big guy on the fly above:
Good luck man...you'll get 'em this spring!