The son of a family friend is going to Missoula Mt. with a school group this summer. They will be fishing the Rock Creek area, and because I am a moron I asked if there was anything I could do? I got the fly list and started tying. Some real basic Elk Hair caddis, Parachute Adams, PMD's, Yellow Sallys, Etc. I tied the 16, 18, and 20's until my eyes crossed, and I'm now tying the fun stuff. Stonefly in size 2,4, Salmonfly in 1/0,2,and Stimulators in 2,4. Are these sizes correct? I've never tied a Stimulator larger than an 8. Please advise. Thank you in advance for any feedback.