
Just to add to the wisdom, in case anyone searches here in the future, I went through this same dilemma.
To cut a very long story short, lots of wheel builders won't touch GS tubeless wheels.
However, HAGON were more than happy to. Their service was really impressive - basically their message was that they didn't have any concerns about rebuilding these wheels, but getting the old spokes
out of GS rims can be a show-stopper.
So they offered a service where for a small fee they'd 'assess' the wheel, ie try to get all the spokes loose - if they failed you just paid the assessment fee, but if they succeeded they absorbed this fee into the very reasonable re-build fee.
I reckon that's a very fair deal indeed.
Paul G