I use materials that are availabe in my area. (I also sterilize, & adjust fertility & pH) Materials include sawdust, wood chips. sand, shreaded corn cobs soy bean hulls etc..... I also include peat moss, perlite & vermiculite. The mix is recorded, tested & when I get the best results I duplicate the mix propotions. (trial & Error) By the way I do have a "ideal" mix BUT am not willing to share with my competion. Why should I give then the benifit of my costley trials.

Decades ago I had a greenhouse and did many rooting experiments, among other things.

I tended to favor starting with fine sharp sand, used by the people who lay tile, and mix in a few nutrients. African violet potting soil was a favorite additive. Less additive for cacti and succulents, more additive for faster growing cuttings.

I have subsequently seen people who objected to sharp sand and who objected to fine sand.

It depends on how fast and 'easy' the cutting being propagated. The easy 'sure' ones I start individually in their own pot with my potting soil. The reason is, I can avoid repotting and causing a check in the growth. Most I start in a mix of about 80% perlite to 20% peat in what is called Root Trainers which allows each rooted plant to be removed when ready with out disturbing the others not yet rooted. Al