I have made my own soil for years, the key for Aroid soil is lots of airation so the roots can breathe and not get oversaturated causing rot and other growing issues.  It's important to have good control of fungus just in case there's any extra moisture built up, so I use charcoal to combat that. I use a mix of Orchid bark as well as perlite for good drainage and airflow to the roots. I sprinkle worm castings because I find that this really helps my plants bounce back after repotting. I add coco husks and coir after soaking them in a special liquid nutrient mix which adds the special touch to make my plants grow and thrive fast year-round.
This mix has never failed me and I love using it on other plants too!
I know you will love this mix as much as I do!