one major thing about watering frequency with any medium is that if the humidity changes, it can mess with your watering timings
I go straight coco but I am in air pots, so I want extra moisture
I used to do hempy with straight perlite and It worked great too
Now with the air pots i use capillary mats made by floraflex beneath my watering system's dispersal trays during the winter, and not during the summer. It helps keep a little extra moiture in the coco when it is the dry season, I have thought about changing to a closed pot in the winter. If I did that I think i'd add perlite and use a cap on the top of the pot if I am worried about dry weather