I ran it 4 years ago at the 380-ish cfs level in a ducky. But I made special note that a small raft like a puma or super puma would be just fine, and I keep considering doing it this year. I have a lot of experience running small side channels of rivers, so the thought of doing it was appealing. However, for those who are not used to continual maneuvering in narrow tight spaces, they might not enjoy doing it. But definitely enough to float a small raft and should be fun
Watch out for strainers, there were 2 or 3 last time I went, and though not difficult to miss, newbies could get into trouble if caught unawares. When I did it, we went only 100 yards before the first bend and log jam, where a 20-something year old with no PFD had pinned a rental Aire ducky deep under the log jam. He was just sitting there on top of the log jam with no idea what to do. I got him to shore, unpinned his ducky and got him on his way, with a gentle reminder that as one who has done some of the biggest whitewater in the west, I always wear a PFD even on very small river like the San Rafael.