Can anyone advise how much flavor and VG should I add to a 15ml nic 100% PG unflavored base to make a 6mg nic 50/50 PG/VG juice?
I'm assuming you mean 100%pg, 15mg nic to reduce to 50%pg 50%vg, 6mg nic.
I'll skip the flavoring part. Flavors are pg, so you'll adjust the calculations accordingly.
Dilute your base with the same amount of vg.
If 10ml pg base, add in 10ml of vg.
You now have 20ml of 50/50 7.5mg. So the pg/vg ratio is solved.
Now think of it this way, you want to reduce from 7.5mg to 6mg. Hence 7.5/6=1.25.
The 1.25 means you want to reduce the nic by a factor of 1.25, or increase the juice level(ml) by a factor of 1.25
So, 20ml*1.25=25ml
So add in 2.5ml of pg and 2.5ml of vg to get a final value of
25ml 50/50 at 6mg nic.