I, too, am trying to find that perfect mix of nic and PG/VG ratio. When I started vaping in Feb 2013, I had an awful smoker's cough. Inside of 4 days of vaping (12 mg/ml 80/20 mix) and no analogs, the cough went away. Two months later with steady vaping and no analogs, a much different couch started up. It is in direct response to the vapor inhale. This AM I tried some zero nic juice. No cough on inhale, but no nic. I think I'll try some 50/50 12 mg/ml next to see if I can avoid the cough, but still get some nic. BTW I was a 50 year PAD MB Reds smoker. The best news so far is no analogs in three months.