Wow, I've never actually read that 40% part on the website...it's a good thing too. I've used a few of their DIY flavorings, and so far they were all very good. The highest I've mixed them is 15%, but I have not used the Thug juice or Strawberry (so I can't help you there). I will say that when I'm DIYing a juice, I would question any flavor that I would have to use at 40%. I would rather vape nic than whatever mystery chemical that makes up the flavoringi might OD-ing with Thug juice then ;D
i've been mixing small batches (5ml) at a time. I'll try going down instead of up. The more logical way should have been to start at 10% and move up 5% every time. I started at 20% because it was easy math wise, lol ~ 4ml pg/vg + 1ml flavor = 20%. Their website said try between 15%-40% but i dared not to go to the 40%.
Thanks for the feedback!