70VG 30PG is so far the best for me. Nic is a contributing factor to TH as well and 13-17mg is acceptable for me. Add a LR atomizer and tons of vapor and i can vape all night.
I've tried pure 48mg PG before, 2 drops into my cart, and 2 vape is all it takes to clear up my mind and feel the accelerated heart beat with a little nausea. my advise is don't try this at home (or anywhere), might just kill you.