Indeed! I would be smashing rocks and charcoal all day to make enough for when I do potting hehe But if it works it works!
I like to keep things as simple as possible so I can reproduce them reasonably accurately and keep preparation time to a minimum. My situation is a bit different though since I can't monitor each plant and water when each is in need.. The overhead sprinklers are set based on what the majority of the plants are experiencing so it needs to be consistent.. otherwise I end up with some too wet some just right and some too dry = not very happy plants.
I think the main point is to fiddle around... try different blends and ingredients until you find one that gives healthy root systems and good plant growth in your conditions. SO take what you read in these posts as a starting point and build on it from your own experiences. Also never be afraid to try something new .. you might find an improvement in the plants respsonse! Just do it cautiously and with a few test subjects first.