For right at a year I have been putting a McNaughton coring system to use. With practice I have become more comfortable with the tool as I learn its (and my) capabilities and limitations. Here are three sets I recently finished. All are Cherry.
The smallest set is 6.5" and 4", BLO finish.
Two footed bowls, 7" and 4", buffed DO finish.
My favorite of the three sets, two more fotted bowls, 9.5" and 6.5", buffed DO finish.
Looking at the difference in sizes of each set it is obvious that I under-shot the coring knife. With a more aggressive (deeper) aim, I could have obtained an extra bowl from at least two sets. But I'd rather err on the "cautious" side than risk cutting through the large bowl in a set. There has definitely been a learning curve to this tool.