I've seen different approaches to the height of a softbank. Assuming you want the most flattering light, is it best to set the fixture above the subject or roughly at eye level?

Depends on the subject, and what the rest of the lights are doing. There is nothing magical about it. Some people look good with the light higher, some eye level. The question is, what light are you trying to emulate? That's how I try to light. If I am in a locker room and it has all overhead lights, it's going to look silly lighting from eye level. I'd probably go 60 degrees up and bounce from right at eye level. If I am doing an interview with an aging woman, I'd have the light MUCH closer to eye level to knock some of those shadows down.

There is no one right way.