So I was trying to get these particles to navigate to different points…and because they’re meshes, they DO have an up vector. But I don’t have to try to work on this system using quaternions, i can do that AFTER i figure out where they are going. I had it stuck in my head that these things had to rotate some number of degrees to orient to the target, then i was going to scale that rotation. That makes this way harder than it needs to be. Steering behaviors are really pretty simple.
Nature of Code covers this quite well - it’s a great resource.