Thanks, guys. Del's video is really helpful--which ones he's concerned about and why, and what he does with the problematic ones.
So. Looking closely at this knot, a few things I notice: It's very solid--no bark around it or pith in the middle. It is more toward the belly than the back. And it's about 1/2" across both ways, probably too big to just ignore. There does seem to be a little crack toward the middle, and a much smaller sub-knot underneath. Here's a better close-up of the knot.

I'm wondering if my best option is to just carve it out, approximately where the pencil line is, and hope there's enough wood left to not make a hinge...maybe put some extra sinew on that spot. The back is highly crowned, and I'm hoping to get about a 50#er out of this, so I'm not sure how much wood I'll have to remove from the rest. Thoughts?