Thanks Robert.
Steve, I know just what you mean, about the contrast & mid-tones - if I were printing, this would be a multigrade number 5! (super-contrasty). The sky is the product of a red filter (in software) to really drop luminosity of the blue right away, and I pushed the whites and blacks a little to try to keep a bit of sparkle in there.
I'm still working in LR and Silver Efex. The problem I have with On1 right now is getting exporting right: either pictures come out soft or crunchy/noisy, and I've not learned the export side properly yet. I probably could have done this in that software, but I'm still staying comfortable with a combo that works well for me. It's really hard to change workflow once a pattern is established, and I know what I need to do to get the result I want.