I vaped 18mg for about 6 months and found I wasn't getting enough, I bumped it up to 22 - 24 - 26mg. I find around 26 is OKAY, but when I start my DIY stuff I am going to bump it to 28mg.
I vape between 4 - 6ml a day. I don't get any of the things you are describing. I don't drink large...