what kind of RY4 and 555, vendor wise, do you normally like?
If you want something more dry and cigarette like, I'd go for vaping zone 555
If you want something more sweet and Halo Tribeca-like, I'd go for TPA RY4 Double, and grab some acetyl pyrazine while you're at it
Ethyl Malitol is good to have on hand for these experiments, and like you said, caramel and vanilla. I really like FA caramel and TPA vanilla bourbon.
If you want something more dry and cigarette like, I'd go for vaping zone 555
If you want something more sweet and Halo Tribeca-like, I'd go for TPA RY4 Double, and grab some acetyl pyrazine while you're at it
Ethyl Malitol is good to have on hand for these experiments, and like you said, caramel and vanilla. I really like FA caramel and TPA vanilla bourbon.