Like I said though, caveat emptor becomes difficult when they give inkjets names like "Platinum".
As to RH, where I live the RH can be 15-20% one day and 80% the next depending on the weather. In AZ it WILL vary widely. So can sun exposure, temp, etc.
Even in more temperate climes, it can vary widely.
Example - A house heated by gas will have a higher RH than one that runs off of electricity. One that has no A/C will experience different conditions in the summer than one with A/C.
Which is why I say you should stick with what you know works.