Nice work Trevor,
I asked the same question a couple of years ago, and the fellow I was talking to said he cut em out and then spot sanded them in, (simple idea)
I used a 9 inch place for radius cut it out sanding to the line, then cut the insert and spot sanded it in. Trevor your design is so intriguing I may have to give it a go (if you dont mind)
Regards
Mike
I think the trick was to add a linen phenolic spacer.