You write that "The olfactory bulb can vary in size by up to 3x, depending on "age and olfactory experience", so perhaps (we're making this up) with more usage your olfactory bulb might actually get bigger" which certainly does not seem out of the question. What we can assume with even greater likelihood is that the sense of smell works better when regularly stimulated. Even if your method did not have any commercial applications in entertainment it could likely (at least if this method scales beyond 4 distinct sensations) have therapeutic potential for people who suffer from blocked noses, chronic sinusitis, allergies or other conditions that block their sense of smell for physical reasons. It might even be used by Sommeliers to retain the capacity for their tradecraft while unable to use their actual nose while suffering from a cold. As we know that there is a strong association between smell and memory there are many other useful therapeutic and educational applications that come to mind if this technology can be made safe for broader consumer use. Right now, regardless of protocols used, you are somewhere on the spectrum between shining nascent lasers at your eyes to determine whether they work and emit light output (which doesn't scale with an increase in power) and the nobel prize worthy quadrant of Jonas Salk and Barry Marshall. While I do hope you succeed and I'd hate for you to be overly cautious I also hope your (olfactory) neurons survive!