I have recently got a KFMV3 it is working wonderfully i am using 0mg juices now i just stepped down from 3mg a few weeks ago i found what works for me is a mouth to lung tank with some menthol juice, I absolutely love it! My shop sells 30ml's of liquid for 14.99 i go through bottles in 2 days and thats mouth to lung vaping, I asked what they use and they told me 100% VG and menthol crystals so i went out and ordered VG and some menthol crystals from ebay. Now i can't use PG it causes me respiratory problems menthol and VG has that cold feeling but is also very smooth and full feeling, Sorry for the long message but can i mix some menthol crystals with VG to make a max VG menthol juice? I have been going through way too much i quit to save money haha 
So sorry if my English is bad it is not my first language thank you
So sorry if my English is bad it is not my first language thank you