Sounds like you are burning the coil/wick, maybe on a longer or slower drag than your normal. Higher VG can be accomodated in a tank but with a big cut in power -- even if you can get one acceptable, it would still do much better with a thinner juice. If really avoiding PG, could try 1 drop distilled water per 1-2 ml of juice, well mixed. I dilute some dripper juices to use in clearos, haven't decided if using some water or just PG is better (also add nic, I use these in dripper also so they're 3 mg). I found some of this -- 30/70 PG/VG -- was OK undiluted in an iSub, but turned down to 20 watts from 25+. Thicker juice might be Ok at 15, 12 watts? OTOH, I had no problem with a small clearo and wholecig juice, which is no PG -- but has 5% water.