well I went ahead and ordered from wizard labs 48mg PG, 100%PG, and 100%VG .... the ejuice me up calculator will be my tool for mixing it
That will work just fine. I recently started getting into DIY myself and was confused about what level nic I should by as well.
The biggest reasons for buying higher % nic liquid:
-Ability to make all different levels of PG/VG ratios and nic content.
-Cost (though it's fairly insignificant in my opinion)
-Can store easier (as many people seem to freeze their nic liquid)
The example given to me was if your target nicotine level was 24mg, and you purchased 48mg 100% PG nicotine liquid, the lowest you could go to get to your target of 24mg would be a 70/30 PG/VG mix (w/ 20% flavoring). Not 60/40, not 50/50.
In your case, because your target is 12mg, you don't necessarily HAVE to buy a 48mg+ nic liquid, though you certainly can. You will just have to do a little more cutting/mixing to get to that 12mg target than if you had purchased the 36mg.
And with the calculator to help it becomes incredibly easy to figure out the proportions.
Good Luck!
P.S. The post suggesting buying 12mg nic liquid in both PG and VG was just offering up one of the "easier" methods to start mixing your own liquids. Having both allows you the flexibility to make a nicotine base ranging from 100% PG to 100% VG, and everything in between, while still maintaining that 12mg level. You also eliminate the need to add any additional PG/VG in order to cut down the nic content.