Gear Dog, take this with a grain of salt...
In 2009 I put on Shelly's without understanding the gauge situation. This was either the last week of April or first week of May, definitely weeks before anything else had water. We had slightly more than the minimum CFS on the combined gauge (N + S SV), when we thought we were reading the NSV gauge. So roughly we had 1/2 the recommended flow, but as mentioned above you can't necessarily do the math that way. Anyways, we had a fun time, definitely low, but not brutal from my recollection. I think we agreed we would want it again with more water, but it was fun. The dam was probably the sketchiest drop at those flows and can probably be portaged on the right, but it's an easy move. Apple valley was especially bad and we had to do the butt shuffle over some of the shoals, but we did not get out of our boats. The apple valley section is my favorite developed CL II run anywhere. We encountered some land owners who told us we were out WAY too early and the water wasn't here yet. After we got home, and called it good on that run until there was more water, I realized the mistake we had made.
All that said, I've paddled Shelly's really low, and high enough the bridges start to be a little scary. At every flow, the creek feels shallow and rocky.