Just need your expert advice. Love to catch the wild/native steelhead and get just as much gratification letting them swim back and make more for me to catch. I've always heard that 20 inches off their length is a good estimate for weight, but does anyone have any other ways of approximate weight. I have a little scale but I don't like spending a lot of time with these fish out of the water. Maybe a quick picture and that's it. I've always went with instinct, then they are always as big as you want them to be???

Chromeslayer, check this link out, should answer your questions.
http://www.piscatorialpursuits.com/weightcalculator.htm

I carry a piece of string with me. I get the length and tie a knot. I then get the girth on the other side of the knot. Then use the formula to estimate the weight. I hang the strings with a picture of the fish.

This is a great way to say "I caught one this big" as you stretch out the string!

I have used the following formula on hatchery fish and it seems to come within a pound (+ -).

24 inches= 4 pounds
add a pound for every inch.

ie. a 30 inch steelhead should be 10 pounds.