charlie b wrote:

Will be getting 200 bf of 4/4 S3S QS English Sycamore soon.
This is Acer Pseudoplatanus in the maple family and not
the American sycamore, which is apparently much less stabile.
English sycamore is the stuff often used for violin backs.

European sycamore for instruments, IMHE English would be a bit
low-end (but I'm no luthier)

Anyone out there played with this stuff?

Lots of it. It's not a common plantation timber, but there's a lot of
odd trees to be had as urban clearance and storm damage. Pretty stuff
with an attractive and small-scale figure, so I keep using it for small
boxes and the like.

You'll be wanting a scraper plane to finish it. Oils are a definite
good idea in finishing too - you want something to draw out the figure
before you slather a film over the top.

Seems pretty stable as timber, even when thicker than instrument bodies.