Trust me been there done that. We all have.
It’s important to do single flavor testing. I know some people think we’re stupid and wasting time, every time we saying it, sadly it’s the truth.
Taste is subjective and I hate saying it, because it sounds like a dumb excuse or scripted evetytime, but even that unfortunately is the truth.
Take a shot glass and fill it with water, pour 1 drop of flavor in it, swish it around in your mouth and spit it out. Continue adding drops till you taste it.
Another method, grab cool whip, take a teaspoon full now add drops of flavoring. Count till satisfied.
Next method, grab 2.5 ml of by or 10ml of vg, drops of flavor and count.
Some people will just taste the concentrate, I do that too sometimes when I know it’s not a sc or alcohol based.
Of course all these methods don’t reflect the loss of flavoring when vaped, or shows how the flavor changes over time, but it’s a good indicator and gives you the base percentage you can build on/from/off.
When new to diy, I always recommend a 2-4 flavor only mix. Perfect that, then move to other and more flavorings as well as more complex recipes.
Learning to build from scratch helps you more, than copying recipes and not knowing why it’s done that way. None of the less, reading up on highly rated recipes with notes is very helpful.
Anyways, it doesn’t cost you more if you single test first, because as you said, you’re wasting more flavor trying, instead of finding your personal spot.
Either way you choose, I hope it’s satisfying at the end. If you like help im sure people are willing to answer, if you want commercial only, great too.
But I thought I add this, because diy and percentage is always misunderstood by a lot of people. There’s no flat and generalised numbers, but it can be a helping help most of the time.