These sea-run brown trout are most often caught with a small nymph, a scud pattern in size 14 or even 16 (try landing a 20 pounder on a size 16 nymph hook!). But they will also come to swung flies (like Collie Dogs or Sunray Shadows) or even skaters. The guides thought your Fish Madman Flashback Bug reflective foam-backed skater (which I know from personal experience is just a killer pattern for steelhead in B.C.) was too big, but I gave her a go and pulled up two nice fish from the depths! Next time I go down to the Rio Grande I will start every morning (it’s calmer in the morning, by noon it’s blowing 30 miles/hour or more) by gently skating one of your flies across the run before ripping it up with sink tips. I’d also try some of your smaller hitch flies as well and I’m going to try all the above on steelhead next summer and fall in BC.
Cheers
Fraser