Well, the one shots should help you figure that out. But, I doubt it is vaper's tongue. It sounds like you've tried a lot of things and haven't met with success yet. One shots can build confidence and also allow you to steep your other juices longer. Some juices (tobaccos in particular) just require long steeping times . It may be a simple as waiting, or you may need to try some different mixes and experiments.
It does take time to get used to DIY if you were used to very strong flavors, I think. To me, nowadays, commercial juices taste overflavored and harsh.
I started with single flavors that I allowed to steep, to determine individual steeping times, and then combined them in my tank at first. It isn't the same as steeping together, but it did give me a sense of how my flavor "building blocks" progressed and the varying steep times. It was a slower start and I also had some storebought juices that I would often combine with that same flavor, a) to ease my transition and b) also gave me more information about one particular flavor.
This slow start enabled me to figure out what I liked, what I didn't, and I did a ton of (commercial) flavor testing before hand to figure out my flavor profiles, what I liked, and what I didn't That gave me confidence moving forward with recipes *I* created, not anyone else. My tongue knows what it likes, and now I know how to provide it with what it likes. The gradual transition got me "used to". DIY. I can flavor for others, but I usually use more flavoring, especially if they are used to vaping storebought. That seems to be working out for them, and I try to get at least a primary flavor in there that is going to not require a huge amount of steeping. Sometimes I will do a "quick and dirty" heat steep water bath to get things moving more quickly, but my preference over time seems to have gotten more subtle and I flavor at fairly low percentage (5--8%ish) and am a "reluctant" sweetener.
Best of luck, but I think the one shots may give you some of the confidence you need. DIY isn't rocket science, but it's often plodding along slowly, especially in the beginning. I kept my expectations low at the start, knowing I was working toward later success, and that helped too.
Best of luck!
Anna
