maple finish
Those are all good suggestions for clearest possible finish. A key factor is the bowl use. If strictly in the gallery, anything is fine. I want three things with maple: 1) highlight the figure, curly grain, etc. 2) give natural look and feel and 3) if bowl will be used, give a more durable finish certainly than Krylon. I follow what Jimmy Clewes does--apply a light (underscore light) coat of sanding sealer like Zinsser product with alcohol/shellac base usually on the lathe. It does bring out the grain but adds much less color than applying an oil or varnish directly. Then follow with a salad bowl finish like General Finishes if that is the use. Some tung oil formulations are lighter than others and give a very good finish on top of the sanding sealer with much less darkening but good grain highlighting. The exterior water based poly contains a top UV filter I have used very successfully on box elder to preserve the color and give no darkening but not for bowls seriously used or where the grain needs to be highlighted.