I'm just looking for more input from anyone who has tried the Double Flavors from DIYSmokeshack or anywhere else.
Also, if anyone has tried their DIY flavors or tabacco essences, how did those work out for you?
I've found flavors to be too mild so I'm thinking either trying double flavors or try adding a few flavor drops to what I have.
There are a lot of inexpensive methods of adding/creating new flavors depending on your budget and willingness to experiment. The majority of users here use either flavor drops from companies like Capella, or 'candy oils' by Lorann oils (most Lorann flavors are not oils but are water based, people tend to stick to those.)
You can use strong commercial liquids (either 'blanks' with no flavor or flavored liquids) as a base for your mixes, but you have to keep in mind the strength of nicotine solution you need. If you use 24 milligram liquid in a ten milliliter bottle, your adding five milligrams of flavoring will cut it down to 12 milligram strength. Spreadsheets can be good for doing the math necessary to get the exact mixes you want.
So far, the only effective sweetening I've found (and I've tried honey, sugar-water and syrup in atomizers) involves adding pure sucralose liquid in small amounts (1-5 drops per/10 milliliters). It works best with actual flavorings. Used by itself, it does very little to change a liquid's flavor, probably because it lacks any olfactory component (taste is strongly influenced by the sense of smell) but it is very good in combination with other flavoring-agents.
For further information, you can search You-tube which offers several video tutorials on the subject. There is also information on juice-crafting in the Modder's section of this forum.
Hope you found this useful.