I agree with getting the heads flowed before and after.
Also, I suggest getting at least one or two more heads and practice on the other heads. Grind until you make a hole so you know what it looks and feels like. Learn how you use speed and pressure to get the shape you want. What you use and need may be different that what I use but that doesn't make one right and the other wrong.
Work with different sized and shapes of cutters so you learn how each one changes the shape of what you are cutting on.
SHAPE IS JUST AS IMPORTANT AS SIZE. Work to get the surface as flat as you can. You don't want a bunch of troughs and stuff on any surface.
You'll never learn if you don't do. Keep us posted.
