What flavors and %'s are you using for your pastry base???
Pastries, even plain ones, in RL are lighter and have a natural sweetness. In vape juice they can easily stomped out by other flavors. And sweetness will be enhanced when using other sweet flavors.
If I were to use FLV blackberry in my croissant base I would start with only 1 drop/30ml and go from there. I'm confident that would not drown out the croissant yet still give me the berry flavor. And that may also be too sweet so I would add a drop of WF Mora (Blackberry) to bring some tartness to balance it out.
Do you have WF Mora (Blackberry)? That is more tart. If you are going to drop the FLV to 0.5% I would suggest going with 0.15-025% Mora. The Mora blackberry will clamp down the FLV berry sweetness.
If you don't have that... do you have a more tart berry? Really doesn't matter which kind cuz you can blend it in (drops) so your FLV berry is still the main note.
Alternatively, do you have TFA Acai? At low %'s it's a good additive for reducing sweetness.
Using
@FranC's tip... 0.5% would help tone down the sweetness of FLV Blackberry. She used to use 1%, but, over the last several months Frannie is leaning "slightly sweeter" with flavors. Might even get her using CAP v1 sugar cookie again.
If you use acai and go with 0.5% of your blackberry I would start with 0.15-0.25% acai.
Hope that helps.