You can use the screwed on conical accessory that Dremel makes to do this.

Long ago, without prior experience, I did several mods on a Goodtime that I got used, for a song. The scooping is shown in the photo. I used a Dremel with some bits I can no longer find. They were not "sintered" or "burr." The closest to what I remember seem to be called "rasp."

If I were ever to do it again (highly unlikely), I'd only do the thumb scoop and keep all the frets on strings 1, 2, and 3.

I don' know what knowledge you have of Dremel tools BanjoNZ but knowing something about woodworking I'd suggest you check into a Dremel (router) base. That will help you maintain a fairly consistent roughed-out scoop depth, and the base would prevent accidental tool grabbing and gouging if trying to 'freehand' hogging out the scoop. 'Control' is the operative word to create a true and professional quality result.
Then, if consistent, pretty, and relatively smooth, you could maybe take the next finishing step with a fine cut 'MILL' file followed by 360 grit silicon carbide paper followed by 400, 600, then finished off with say, oil and 1200 grit but finally 2000 grit would really make it shine and impress the wimmin folk.

Check Amazon for mini Swiss files. You might have better control for a delicate procedure.

I've got a buddy that did his with a buck knife. Turned out great.

Don't overthink it. 

quote:

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Originally posted by KCJones

I've got a buddy that did his with a buck knife. Turned out great.

Don't overthink it. 

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I went to a workshop by Chris Coole and had a chance to ask him about his Vega.  He told me he carved out the scoop with a Buck knife, cut the frets with some side-cutters and smoothed it all up with a rasp and a file.  True story.

......there's the quick-and-dirty route......then there's brain surgery. Must depend on one's degree of either being impatient or being cursed with standards of workmanship.
Whatever works for some folks OK is OK.