I did some of my own research too and was very interested in the properties of spike oil as turpentine gives me headache and sore throat. My findings are that turp consist of 85% of alpha-pinene, while spike oil is 80% mix of linalool, 1,8-cineole and less camphor. If to look at those chemical SDS (safety data sheets) I could not decide what is less evil for my health as all of them are nasty chemicals. I could not decide what I will want to sacrifice and still use odorless paint thinner. If someone find a good article that talks more about health exposure, please do share.
My main concern here that there is also quite a lot of marketing involved to make things look less dangerous. That is the reason I try to verify everything myself, but I get stuck sometimes.
Please make sure that you have a very good ventilation for any of those chemicals present in your studio when you have to handle them.