This sounds pretty scary and you were prepared with those life vests. When I learned to flyfish my mentor went down and he got water into his waders not having a belt. I only heard him yell then cuss. I thought he had a fish on but when I caught up with him 20 min. later he was soaking wet and wide eyed stone drunk but sober from a near drowning and sitting on a boulder. I haven't invested in a fishing life vest yet but I should have by now so I'll make this a priority. I never even thought about this floating down the Snake with a guide and he didn't even offer one. I gone down twice in water only up to my knees once near Chatfield Reservoir in Colorado and another near Bend, Or. The first time I lost my rod and reel but found it 150 yds downstream. The second time I lost my wading staff. So your recommendation is a good one even for this able bodied and well balanced ex-windsurfer and volleyball player.