Hey guys.
After many hours spend researching on the internet, I finally managed to get drawings/plans for the front shims. The author of this blog (https://shufti.blog/2012/07/17/vanagon-syncro-front-spring-pad/), Alistair Bell, shared the original plans from French syncro club with me.
I've redrawn them and am attaching plans here.
Best regards
Beau