Hi Mike,
I like what you did with the maple core. I used the same tool to create multiple 'extra' pieces.
I would like to suggest an alternative finishing method: Use four coats of brushed-on clear Min-Wax polyurethane (gloss or satin). After the first coat has fully dried use oil- free 0000 steel wool to totally remove the poly (down to the surface of the wood). Brush on the 2nd coat, let cure and steel wool off. Do this four times. The poly will seal the wood as well as act as a filler at the same time.
After you remove the fourth coat of poly let the bowl sit for 24 hours. After this time period has elapsed check for any fingerprints (use 0000 steel wool to remove). Apply a coat of Renaissance Wax, allow to set for ten minutes and buff using a soft cloth (an old terry cloth towel works just fine). Caution: Your bowl will become extremely slippery so be careful it doesn't 'squirt' out of the rag! Don't ask me how I know this. Let the bowl sit for one hour and apply a second coat of Renaissance Wax. Let sit for a minute or two, buff and sit back and admire your work.
The one nice thing about using the polyurethane finishes is that it doesn’t give off any fumes like BLO, Waterlox and other shellac and varnished based finishes do. This is especially true when making lidded boxes. Lidded boxes finished with Waterlox, shellac, etc. smell like an open paint can when the box is opened.
One other suggestion is to use crushed stone to replace a bark inclusion or a knot. Some turners use brass shavings, etc. but most people are more impressed with turquoise than brass shavings from the key machine at Home Depot.
One other thing to keep in mind: The finish and embellishment on the bottom of the bowl is just as important as the upper portion.
Bill Baumbeck