As it says if you use the 0.40 oHm coil use lower strength nicotine salt juices. If you use the 0.60 oHm coil you can stronger strength nicotine salt juices.
Not used nicotine salt juices. I have always used 18mg/ml nicotine strength free base ejuice. Some suggested if I used sub-ohm coil/s I might desire using lower strengths. Did try that but found I prefer the 18mg/ml.
Ultimately the choice is up to you. If you try something and it seems to do alright for you, keep using it if you like it. If you try something and it suits you but you want to try something else, you can. The choice is yours.
Simply because someone else says that this works does not have to define you or what you do. This applies to living, vaping, religion, whatever. We all have freedom of choice and can change our choice as we desire. Granted there may be consequences, be aware of that, yet still the choice is yours.