NG,
I believe that ALL steelhead are worthy of NOT being being cracked on the head, but having said that I also feel that those with a clipped fin should be harvested. It's why they were produced in the first place. However, one exception to this are downriver (kelt) steelhead which I see no reason to harvest even if clipped because their palatibility is low and you can no longer keep them out of the gene pool since they have already spawned.
Of course, all this depends on how hungry or deprived you are. If I'm starving I'd probably keep anything, but on the other hand if I'm starving I'm sure not going to rely on steelhead for my source of food either. The way I see it, just about any other fish would be cheaper and easier to get for food than steelhead.

Great question, which should stir some good debate.
From my experience I have found the 9 am to 11am to be the best productive period overall for catching winter steelhead, since it has not only been a consistent time but a more extended bite period as well. But it generally understood that the first and last light of the day, although a much narrower time period, is the most consistent and reliable time to catch steelhead in general and summer runs in particular.

Hope this helps.