Serinde, the Soie d'Alger shade card I've got (well, a pdf version), says that there is a separate shade card for Soie Perlee, Soie Surfine and Soie 100/3, but doesn't say where to get it

I can't find it on their website.
Needle in a Haystack do a good range of Soie Perlee with clear photographs
here but I understand that's no substitute for a shade card

and the only conversion tables I can find are between DMC and Soie d'Alger.
I'll keep looking!