Some more ideas:
https://somervillebikes.wordpress.com/2020/03/12/how-to-install-metal-fenders-part-iii-installing-the-stays/
That looks really smart. Just about making that jig...
@swmlon started
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Some more ideas:
https://somervillebikes.wordpress.com/2020/03/12/how-to-install-metal-fenders-part-iii-installing-the-stays/