The black sides & neck look great, I have no doubt the back will be just as nice.
If your going to attempt an edgeburst, I'd stain the top a medium brown let the stain sit for a day or two, then clear the whole top.
Just a couple of light coats, were just looking to seal the stain.
Next take the guitar body and using the outline of body transfer the shape to a piece of heavy cardboard.
If all went right you now have a cutout the exact size & shape as the guitar top.
Now you need about a dozen plastic handled 1/2" push pins. That would be about 13mm for you more sensible metric folks.
Measure in about 4 to 5 inches in and draw a line approximating the body shape, just smaller, and start sticking the pins into the cardboard in roughly the shape of the guitar.
This will hold the mask an even distance off the body.
Position the mask directly over the body and spray the top all the way around the edge, holding the can at about a 30 degree angle.
If this angle isn't giving you enough color on the guitar face change the angle a bit. Just make sure that you consistantly hold the can the same way.
The closer the can is to being straight up & down will determine the width of the burst.
This should give you a nice seamless dark edge, the idea is to have heavy solid color around the outside edge, while the inside edge
has a controlled fade into the brown stain.
I recommend doing a few test bursts with a mask on some scrap first, just to get a feel of what's happening as you go.
I saw a tutorial years ago that outlined this and it has changed my life forever.
However I looked and couldn't find it. Wish I had bookmarked it.