Smitty,
While I haven't stopped there this summer, I have spent a fair bit of time on Cripple last summer and previous. My best days have been on +25c afternoons. Seemed there was a little Cutt behind every rock.
However, one morning (around 10:00am) I stopped there on the way farther north. It was going to be a hot day, already 18-20c. After 2 hours I left skunked. Not a rise or flash, nothing. Perplexed, I stopped there 2 weeks later around late afternoon, and did very well.
I believe water temperature was the main factor then, seems to be a late-afternoon kind of creek. I've found this on other Cutthroat streams. But maybe not to the extent I seen there. Many stretches are fairly well treed, so maybe it takes longer to warm.
Although I have seen alot of vehicles parked there during my travels this summer. Surely nobody has been filling their cooler with 7" Cutts.