Recently I went out to go after pacific rockfish on the fly off a jetty here in Oregon. It was a blast. From the process I learned some good information about fly construction and design. By no means am I an expert on catching these fish, but I have tied flies for freshwater predators and have applied the some of the principles I learned from freshwater designing.
You will burn through flies. The jetty is an unforgiving fishing environment. The rocks are incredibly abusive on flies especially lead eyes. I learned this the hard way. If those eyes hit the rocks at any speed they’ll snap right off. Clousers are great flies. They work great and you can crank out a million of them in a session. I’ve switched over to brass eyes and epoxy to keep them together a bit longer than average.
To follow up about simple. You want your flies to hold up. From what I found the best materials are going to be synthetics. These means your Steve Farrar blends and EP fiber are going to be your best bet for longer/ slimmer flies. Bucktail is really nice, but the rocks and specifically the fish will tear it apart only after a few grabs. The other synthetics I use are finesse chenille for gamechangers. Now If you want to keep it natural, rabbit is a great material. It moves extremely well and slims down when wet and stripped. The only downside I have with it is it hold a ton of water making it hard to cast. If you tie these large then I would use heavier rod so you can use the line to cast it.
So I mentioned lead and brass eyes above. These are totally optional. This is, of course, dependent on using the right fly line. If you ever see me at a show or talking about fishing and casting flies you’ll hear me go on about how important your line is. If you’re using a heavy enough line and the right leader material you don’t need your flies to be weighted at all. But if you must don’t be hesitant on the weight, I use extra large brass eyes on my flies I want to sink.
Don’t go too nuts on flies. When I get into a new discipline within fly fishing I become a research machine. I want to know diet, migration patterns, habitat, spawning seasons, personal experiences, etc. What I can tell you is that the fish rarely get picky with flies. They might want a size, color, or silhouette, but that can be accomplished with about 3 different patterns: clousers, woolly buggers, and deceivers. You get a slim profile that can be tied with thousands of materials or colors. Also you get a smaller fly with buggers. Finally a bulky baitfish look with a deceiver. Color does seem to matter based on the time of day. When its bright go with bright colors, and opposite when its dark. My go to colors in various combos are white, chartreuse, blue, black, yellow, orange, and purple. With that you can match any “hatch”.