I just like to make a slight correction to a previous post if I may. If your target nicotine strength is 24mg/ml,anything you add will lower it. Some recipes people use up to 20% flavoring 24-20%=19.2mg/ml. If you are ok with that then you are good . If it must be 24mg/ml,you need to start with a higher mg/ml nicotine solution. The aforementioned 20% flavoring ratio is high but depending on your chosen flavorings,not out of the realm of possibility.
Therefore,I have found it best to use stronger nic base and dilute with flavorings and added pg/vg.