Barb, if you planned this right, and had some coring practice, I see where you could get 3 pieces from this. A small plate, about 10" round from the center, and two platters the same OD as the piece will allow. Most people when coring will try to get a bowl from the center, move the corer back a little, get another a little large that the first, and then another larger that the last. If they are good, they might be able to get the last one with what left.
Mike Mahoney could get 7 pieces from a blank about 6" thick. But we all can't do what he does.
I did see in the instructions on the McNaughton how to turn the OD first, then core out successive pieces all the same OD size by starting from the edge.
The last successful coring I did was to start with a piece about 14 3/4" round, 3 1/2" thick. I actually made 3 pieces from it. One shallow bowl from the center at 1" deep, the next was 1 1/2" deep,and the third was 2 1/4" deep. That gave me total depth of 4 3/4" depth combined from a 3 1/2" thick piece. All are still pretty thick as they are still a work in progress. I posted a thread here about them, but don't know how to retrieve it from the annals of WB history.
One advantage of coring from the edge is the piece can be supported by the Tail Stock. There is nothing more comforting than knowing your work piece wont jump out of the jaws while working it. ............ Jerry (in Tucson)