Re: best crappie fly ?
I do fairly well with crystal buggers in size 6 or 8. I'll weight the buggers, with wire, cones, beads or barbell eyes depending on how deep I need them to sink
Another fly I like is a simple feather wing streamer/ wet fly. Hook size can be any you like, but I usually go with 4, 6 or 8.
It's nothing more than a hackle fiber tail, often I use red, body of silver or gold flat tinsel, ribbed if you like, but I don't usually, a wing of a pair or 2 of white hackle tips, and a sparse collar of any soft or webby white hackle you have. I tie these on streamer or nymph hooks of various lengths. On 2or 3X long streamer hooks it looks more like a streamer, but on shorter hooks, it looks more like a wet fly. Either way, doesn't seem to matter. I don't add any additional weight to these, as the weight of the hook is all you need. I cast them along edges & just let them sink slowly, counting them down & stripping them back with short strips of the line. Great for any relatively shallow water, say 4 ft or less, but can certainly be used in deeper water.
Remember, no one likes to be behind the big truck, but that's better than being under it!