I have not gotten this combo to come out right yet, so you'll still need to experiment.
I have tried 10% total flavor at 50/50 and it tasted like bad popcorn, lightly flavored bad popcorn, but from that it seemed that the blueberry is a less concentrated flavor than the cheesecake.
I went up in total flavor percentage and put it in an 80/20 PG/VG mix with the total flavor being 15% with Blueberry being 75% and Cheesecake being the remaining 25% of the flavor. This actually tasted fairly good on the day of mixing. But I let it sit for a week and tasted it again and it tasted like feet, not horribly bad feet, but feet nonetheless.
I am sure I am missing something and have not gotten back to it to work it out. Was thinking of adding in some vanilla and/or adjusting the ratio of blueberry to cheesecake, but it will have to wait for another time.
Mix small batches and see if you can crack the combo ratio and let us know?