Here is a bit of a sneak peek, since I have the top already cut to shape (plus 5mm extra which will be trimmed after closing the guitar):

Nothing glued yet, just to get an idea of how it'll look later.

The mechanical parts are a CompactLine 8050 from Sorotec (German manufacturer), Spinogy X22 spindle, and the electronics are custom.

For cutting the rose pattern I used a 15° "RazorPoint" V-carving bit, which worked remarkably well. I have basically zero-radius corners at the bottom.

For the wooden layers: Construct the pattern on paper, transfer it to the wood, then cut with a scalpel from behind.

For the parchment layer: by using a mixture of specialized stencils and gouges of varying radiuses.

It dampens the sound a bit, makes the instrument sound less bright. Renaissance & Baroque guitars are much brighter in tone than modern guitars, so without a rose, these might sound too harsh.

I tested a 3d-printed rose insert for my classical guitar and it just sounded... well, not unpleasant, but muffled, like hearing it from a distance, or from the next room. Modern guitars naturally sound more mellow, so this was too much. Sounded decent with a capo on 5th fret, though.

Does it add extra visual depth, or [...]

Exactly this! It is also slightly larger than the cherry layer, so ot looks like a black outline. Cherry and Ebony layer are each 1mm deep, so the ebony gives an interesting effect when the rose is viewed slightly from the side.