Using the parting tool to core a bowl would leave you with a central cone shaped blank that would be fine for one of the bowl like yours Les. Personally I don't do enough bowls to make the bowl saver a worthwhile investment but if, like Steve you make a lot of larger bowls it is definitely a worth while investment. Another way have seen it used was by making sets of bowls, usually three, from highly figured wood so that each one has similar grain and figuring in it. Looked good as a set. The coring system is perhaps something I would put on my 'one day' list along with a magnum lathe, floor standing pillar drill, startrite bandsaw..................
Pete