If it puts your observing self into a subjective posture, then the observations must be made from there. If you cannot do that then it means that you have to develop subjective ability to observe or just leave the substance aside and use some other substance or method. In kundalini yoga practice also, we find that in some phases of the practice, objectivity is snatched away when kundalini rises but we have methods, particularly the locks to help to settle that. We also have higher meditative states which also take away objectivity but by meditating on and on day after day, the student eventually gets clarity even in the states of consciousness which initially were totally subjective.