WBranch;
I've fished both of these rivers, at least 5-6 times every year, for the past 25 years or so, give and take a few hours.
After my first 10-15 trips, over there and "thinking I knew enough, by then, to know what would work and what wouldn't"............. I finally got smart enough to WAIT until I reached the area, before making my fly choices!
There are a ton of variables, when fishing these two rivers and unless you live, on, either one or at lest very close by, you can't and won't be able to keep track (day to day, week to week), of all those changes.
In other words............. "what killed 'em, in June of '07, they may not even LOOK AT, by the time June '08 rolls around. "Water levels", "wild fires", "lack of hatches", an "over abundance of a certain hatch", these things all change the outlook and results of these rivers.
Of course, I'd pack and take along the "always go to drys and wets", which are standards on about any moving water. Personally, I'd take #12 down to at least the #20s bracket. Scuds, a decent nymph selection, BWOs, Elk Hair Caddis, (A, MUST HAVE fly!) and even some #18 and #20 chartreuse Humpies, all, have worked very well for me over there!
But, mainly, what I always do now,is..............After I check into a motel, or pitch my tent, depending, before I even LOOK at the rivers....... I always hit the fly shops and start asking questions!! Almost, ALL, fly shops in those two areas, have up "What's happening, locally" wax boards that are kept pretty well up to date.
These guys and girls, KNOW these rivers and they're always happy to share what they know with anyone. "But a spool of Tippet,(needed or not, it's a nice gesture, to a shop owner!) and you'll be given even MORE advice, on where to fish and with what!!
Just a few suggestions, on my part and nothing is "cast in stone" when it comes to fishing either place!!
Have fun, let us know how you did!!