Mort,
What does it appear like to you is the problem? Why isn't it up to presentation quality? Do you mean the smoothness? Depth? Color? Anything else? You mentioned "highlighting" so I assume you mean really making it stand out and not appear bland / flat.
Figured, light colored wood takes on a great depth with an oil (either alone or with a film building type of finish along with it or over it) and can become quite striking. Unfortunately, it also is likely to yellow the wood a bit depending on which oil you use. Just a top wax, lacquer spray, or non-penetrating finish, for example, will often leave the piece appearing "flat" and with no depth to it.
The Ambrosia and Spalting coloration will really "pop out" when an oil is applied but may significantly darken surrounding areas.
You can always go with a penetrating finish (basically some kind of oil) to bring some depth to it and make things really "pop" then do something over the top of it depending on what you're looking for there. I mean, you can either make it plastic looking or just make it look like an "in the wood" type of finish. Gloss can be adjusted no matter what finish you decide on there.
A good, easy finish that will highlight figure and colorations (spalting, ambrosia, stains, etc.) along with a light film build on the top is what's called the Maloof Finish. There's all kinds of varieties of this general finish type but it's basically just...
1) An oil (Pure Tung, Boiled Linseed, etc.)
2) A film finish (polyurethane or varnish mainly)
3) A solvent (mineral spirits, naptha, etc.)
All in equal parts. Apply as much as the wood will take ... wait 15 minutes or so and wipe off. Allow to dry overnight. Do this 3 or 4 times and you'll have a great finish. Do it more and you'll get more of a gloss and more of an "out of the wood" finish. You can apply a wax buffing to the top of this after you're very sure it's dry to give it some more gloss and minor protection.
Hope it helps,