Man I couldn't tell you jack about how those 120's compare to 123 Scenars...so I don't know.
I'll note that with that 130gr NORMA, I'm seeing 2885-2860fps out of a 24" (Chrono'd a new lot just yesterday in fact). A good baseline for numbers comparison, but not a perfect representation. I do love that resource though.
Again, it comes down to how much you willing to sacrifice?
You want a 120gr 2600+fps out of 16" in a hamstrung large frame?
or
you want 120gr maybe 2500 out of an 18" eeking out every thing you can from a small frame?
Then at what point do you stop and start looking at a 6mm?