Update for anyone interested: I fished the canyon last weekend. I got to the river at 8 - not sure if I missed the Trico hatch or if it just didn't come off as big as I expected.
Lots of small hatches in the morning from 8-9:30, mainly Tricos and Caddis (didn't see one BWO but they have to be out there...). Fished all morning until about 2 in the afternoon and landed 15 fish while missing another half dozen - nothing bigger than 13-14 inches, all rainbows except for one brown.
I fished various tandem rigs of indicators (small thingamabob, chubby, hoppers) - to nymphs (PT, Trico-emergers/spinners, prince, copper-johns). I had two fish blow up on a small thingamabob indicator so I threw on some hoppers and chubbys on as my indicator, but the fish seemed to like the hookless indicator more than the hoppers
. The nymphs that had the most hookups were pheasant-tails, prince nymphs, and chartreuse copper-johns.
Also saw a lot more bear sign than usual but never saw the culprit. The water levels are fine/clear/cool/healthy, whereas this time last year they were dangerously low.