You should be golden. Keep in mind though that only if you have 10 or less people, are you allowed to take 7 nights, 8 days.
As an anecdote: the lowest I've ran it was at 2.4 from boundary, in an 18' cat with every luxury possible, plus 2 passengers. I ran lead boat and got stuck once for less then a minute or so. Lucky, probably, because my boat was freakin heavy. But I'd cut my teeth on reading low water from Alaska to the salt, sprinkling in several low water Dolores. Maybe that helped? Not too sure.
Now I go much leaner and meaner in a 14' raft. Floats higher and is way easier to move in the middle aged chapter of my life.
I'm hoping to get on a MF trip too. I keep surfing the rec site...
You'll be just fine.
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