I have used the mix below for Peyote and other non-psychoactive cacti I have, with good results so far. I would change the JI mix to JI no.1 or JI seed for seedlings as opposed to potting on, as these blends contain less nutrients. If you use too rich a soil you risk damaging the cactus.
For starting off the seedlings themseles, I have used a thin layer of peat based seedling soil, with the mix described beneath it. This assists germination, but allows the seedling to grow into a decent medium. I don't like to repot Peyote for years after it starts. Torch may be more hardy, as it grows a lot quicker.
Personally I have used Irish moss peat (about 10% total), but the pH level of my mix is neutral. I have never used vermiculite or coir, but the rest of the method ouro describes I agree with. Its interesting ouro has had poor results with hort sand, I can't think why this would be, but would be interesed to hear any theories.
Also, I would always make your own mix. A lot of the specialist mixes sold commercially in garden centres are not fit for purpose.
My mix was approx (by volume):
40% John Innes No.2 Compost (use JI no.1 or JI seed if you have very young cacti, as these have less nutrients)
25% Horticultural Sand
15% Horticultural Grit (also used for top dressing)
20% Perlite
If you can't get John Innes no.2 or would prefer to make your own it consists of:
60% Loam
25% Peat
15% Sand
and then with each 10L of mix, add
6g ground limestone
24g bonemeal
24g superphosphate
12g potassium sulphate
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