lol, "diaper-y"! That is really evocative, in a terrible way. I don't know if we have the same sense of "diaper", you and i, but would tend to associate that with too much creaminess in the mix. I'm new to this too, but my experience has been that not just too much overall flavoring (as others noted already) but also too high a relative percentage of cream-types and/or pastry type flavors will mask or dull or like...absorb fruity flavors. They even seem to compete with one another at times in a mix.
I'm always surprised at how little of those creams and vanillas I need to get a satisfying creaminess or full mouth-feel kind of sensation. Too much of them--and especially, I'm now noticing, too much of the ones that have diacetyl/acetyl propionyl (which I think your bottom three do)--start to get kind of "gross" to me at higher percentages. Not sure why this is.
So the last thing you did was knock the strawberry back to 8% and cut the four creamy ones in half, right? And that still tastes diapery. I'm not exactly sure what you're going for, but if the cheesecakey element is important for your result, I think I would try eliminating at least one of those bottom three flavors and adding a small bit of lemon or cranberry or a tart raspberry (like FA raspberry). In fact, I would eliminate two and add both lemon and raspberry. I don't have all those flavors, so i can't try it, but maybe:
8% Strawberry Ripe
2.5% tfa Cheesecake Graham
1.5% of
either TFA Vanilla Custard, TFA, Sweet Cream or TFA Bav Cream
.75 - 3% each of lemon and raspberry (depending on how concentrated the brand you use is--like, for FA it would be low, but higher for a somewhat equivalent effect with TFA)
You'll still have a good lot of flavoring in there, I think, and I expect it will still seem very creamy. I'm guessing you can do this in a way where you won't really taste either the lemon or the raspberry, but they will lighten things up. And maybe the diminished creams will reduce the diaper effect.
How true!
I'm leaning so much lately I'm practically staggering around.