I had considered doing something to the top to make it stand out from the back but it's extra work and extra chances to screw up a project that has to date gone pretty smooth
My plan was to coat the body in an amber tinted poly, Minwax oil-based PolyShades in pecan. Then clear with minwax oil based clear gloss, cut, buff, and polish. I know the products work together and I've gotten good results in the past.
A burst is intriguing... but again if a chance to screw it up. What product(s) do you use for the color? I want to darken the alder a bit cause it'll help hide my plugged holes better than clear which is part of why I was gonna amber the whole thing.
It's definitely a bit of extra work! But with all the time going into an instrument, what's a couple more hours? Fortunately, the chances of a calamitous screw-up while doing color coats are pretty minor.
I've been using Transtint dyes for more than 10 years now. You can buy them on Amazon, and Rockler and Woodcraft carry most of them in stores.
TransTint Liquid Dyes Store - Homestead Finishing Products
To do a burst, you'll need at least two colors. Fades and MTD-style nebula blends are also relatively easy to do if you know what you're doing. (see my thread with my nine year-old!)
Pretty much any oil-based finish is going to amber your wood tone pretty significantly. That's partly why I think a bright contrast color is going to work really well on your bass - you've already got a lot of amber to medium brown tones going on in the flame figuring. If you look at my build thread you'll see how much darker the natural-finished bass got after I started applying oil to it.
I used to use the Minwax stuff but I was never quite happy with the end result...to my eyes it always looked more like a plastic shell on the outside of the wood. Back in 2009 or so, one of the guys in the LC group gave me a recipe to make my own finish and I've been much happier.
Sherwin Williams and Benjamin Moore both make clear gloss varnishes. Combine this roughly 50/50 with mineral spirits, and a few drops of Japan Drier. Mix and apply. You now have a thinned, oil-based wiping varnish that is cheaper than the big box stuff, and will give better results. As you start to build topcoats, increase the ratio of varnish to spirits and it will form a nice hard film.
The other alternative is the General Finishes Arm-R Seal-stuff. I much prefer it to Minwax. There have been a number of pro woodwork finishing comparison videos on youtube and the GF stuff always seems to win out.
Just make sure you use the high gloss version of whatever you decide to go with. The lower sheens have silica in them that are really good at making your bass look like a cloudy, blotchy mess. Better to start with high gloss and buff out to whatever sheen you prefer. Let me know if you have questions!

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