Brad, who lurks in Benecia wrote (clip) Use a thin parting tool to go as
deep as you dare. Then stop the lathe, lock the spindle, and finish off
with the saw.
^^^^^^^^^^^
Brad, your method and my method arrive at the same end-point. Using your
method, if you make the cut with the parting tool on the bowl-side of the
line, it will not matter whether it is a thin parting tool, since the wood
it is removing is the same wood I was removing in shaping the exterior of
the bowl prior to parting off. I think your procedure is better because it
gets the platter out of the way before you start shaping the bowl.