I use Machinist Mate software to get in the ballpark of RPM and feed. PCNC also has some kind of calculator on the wizards screen that I haven't looked at.
But don't F10 and F11 still bump the feedrate down and up during motion? That is what I've used during a program, and would work the same with MDI input...
Randy "bump up the feedrate until the cutter snaps and then back off a little"