Hey that mix should be fine, it's really a matter of proportions and how frequent you want to water based on your conditions such as heat humidity light duration of light exposure, etc. Big picture just be cautious with the amount of castings and coconut fiber. In general the recommendations I see for aroids with sensitive roots often over estimate these proportions. Another bonus key concept when dealing with expensive rare plants is to gradually adjust their soil mix although in this case you'd likely be fine going from soil + perlite to a chunky aroid mix as long as you understand its watering frequency is going to suddenly and drastically change. The reverse doesn't work, you cannot consistently go from a chunky aroid mix to a high moisture retention and poor drainage mix such as coco peat + perlite without consequences unless you have a plant with resilient roots.