For example, if your friend vapes 18mg nic
juice. It is very easy to make unflavored nic juice. Whether he has 100 nic or what ( I think he may have 100mg but in pg) If he ordered the 0 nic premixed vape juice with like 5 extra flavor shots and then mixed 50/50 with his own mixed nic juice he would have what he vapes.
30 ml of Unflavored 36 nic juice
+
30 ml of Premixed 0 nic with 4 or 5 extra flavor shots
= 60 ml of 18 mg nic flavored juice.
I know this is very hard to write out so you understand what I am saying. The very easiest thing for you friend to do is get deeper into DIY. Very easy to make my unflavored 18 mg nic juice and add flavors to it. And it is fun as well as rewarding. And above all it is "less expensive" than what he is trying to do now. IMO. I have become a bit lazy in my mixing. I buy
vaping Zone concentrated or gourmet flavors which are real strong and use less. I have a big bottle of unflavored 18mg nic juice and I just but it in a smaller bottle, say 20 ml and then add 8 drops of 2 different flavors and shake and vape. Easy Peasy.
Good luck to you and your friend. Have fun with it.
This calculator may help your buddy when trying to mix what he is trying to mix. Just thought it might help.
http://www.ecigvape.com/combine_calculator.php