My coworker had a neuma hybrid. He used to run it at 13 or 14 from what I remember. Many rotaries are suited to certain duties. If you run it really high, and it just 'doesn't feel right' then you are probably maxing it out and forcing it to do a task it isn't suited for.

Many people on here use a Bishop to line, shade, AND color with. It might not be the equivilant to a coil machine running at 140hz loaded, so if you are used to lining with a fast machine, and it doesn't seem 'fast' enough for you, you might have to slow yourself down.

I'm only speculating, though, as I don't own a Bishop, but I know what my other machines do, and I can feel when I'm 'pushing them outside of their comfort zone'.