My thoughts on flash:
It's at least somewhat dependent on water conditions. With poor water clarity, I like a bit more flash in my flies. I fish for stripers over muddy saltwater flats quite a bit and include lots of it because the water is so murky. When fishing over sand where the water is much clearer, however, I use almost none. Last year when steelhead fishing some very chalky Lake Erie tribs, I had no joy on patterns where the only flash was tinsel ribbing. As soon as I switched over to flies with more flash, I had much better results. The opposite was true later in the week when I moved over to some clearer Lake Ontario tribs.
I also like to layer and/or veil it with opaque materials. For example, if I put flash in the wing or body, I will also have something like marabou, bucktail, etc. tied in sparsely over or around the flash. I like to think that as the opaque material wiggles around, the flash "winks" through the gaps, creating a more subtle "inner glow" and twinkling appearance. Of course, that may not be what is actually happening or how the fish perceive it, but I like it as a working theory.
It's at least somewhat dependent on water conditions. With poor water clarity, I like a bit more flash in my flies. I fish for stripers over muddy saltwater flats quite a bit and include lots of it because the water is so murky. When fishing over sand where the water is much clearer, however, I use almost none. Last year when steelhead fishing some very chalky Lake Erie tribs, I had no joy on patterns where the only flash was tinsel ribbing. As soon as I switched over to flies with more flash, I had much better results. The opposite was true later in the week when I moved over to some clearer Lake Ontario tribs.
I also like to layer and/or veil it with opaque materials. For example, if I put flash in the wing or body, I will also have something like marabou, bucktail, etc. tied in sparsely over or around the flash. I like to think that as the opaque material wiggles around, the flash "winks" through the gaps, creating a more subtle "inner glow" and twinkling appearance. Of course, that may not be what is actually happening or how the fish perceive it, but I like it as a working theory.