Best substrate mix for rooting by layering of frankenia laevis species

I need bibliography or references to guide me for the best substrate mix to make rooting by layering of the species frankenia laevis since I need to generate new plants from a “mother” plant.

What I need is something that tells me the percentages to use because I have a general one that is 15% coconut fiber, 20% perlite and 65% vermiculite but I have nothing to support it as a reference or bibliography.

If something is not understood I am sorry, I am using translator because this is not my first language.