FWIW, four 0.6mm holes would be equivalent to 1.2mm (and six of them would be more than 1.4mm but less than 1.5mm). Definitely not in my ballpark - it's well over twice the airflow of a 0.8mm hole. But hey, the original Kayfun Lite was 1.2mm, and although SvoƫMesto made the base hole bigger (for more air) and added an airflow screw to tighten up the Plus for "proper" MTL as well, it wasn't like the no-Plus Lite didn't sell - and 1.2mm is the default on a lot of "insert" tanks, bridges and RBAs. It works for a lot of people; just not for the likes of me.