I guess to start the only way for me to know will be by taste in an unflavored mix. While the Carolina Nicotine sounds attractive because it's USA grown and processed the final judgement will be by taste and relaxation effect. I just don't want to waste any money if it cant be stored for the period it will take me to use up the bottle at 1.2ml per 30ml bottle because that's 83.333333333 mixes and it'll take me a long time to vape it all. If it can be stored in the fridge and not get an off taste for the duration I think it's worth it. If not, no.
You should base the quality of nicotine on a lab assessment coa etc. Something that Carolina will not supply. Chemnovatic uses the same/similar extract process that Carolina uses and supply documentation of impurities etc. All this info is on this site under nicotine comparisons.