I answered my question myself - mostly. Here is what I learned:
Music Editor Inspector
Default Velocity setting (near the top)
Set this value to a % between 0 and 100. This controls the velocity level of any notes you will create with the mouse – either drawn in with the paint tool or double-clicked in with the pointer tool. Notes created from a keyboard device are not affected by this setting.
Velocity setting (near the bottom when notes are selected)
Adjust this setting (0 to 100) to change the velocity of any selected notes. This is very handy when changing the velocity of all notes to a common setting using Select All.
Navigation Lane (at bottom of Music Editor)
With Velocity selected in the Navigation Lane use the Arrow Tool to adjust the height of the velocity bars either individually or in groups. Use the Paint Tools to draw a velocity ramp, curve or other shape depending upon which paint tool is selected. You can also use the Transform Tool (at the bottom of the drop down Paint Tool menu) to draw a velocity ramp.
Edit notes directly in the Editor (Piano Roll)
Hold Alt/Opt while dragging vertically over a note with the Paint Tool. Adjust one note or a group of selected notes.
R-click on a note or group of selected notes. Choose Velocity and, in the dialog use one of the following three controls to adjust the velocity of the selected notes.
- Add (adds a % of increased velocity to all selected notes)
- Multiply (multiplies velocity of all selected notes by a numeric factor)
- Set All To (sets all selected notes to a common velocity setting)
I still have not determined the function of the Velocity controls in the Arrange View track Inspector.