Just an FYI - PG is not harsh. Don’t believe me…try vaping a bit of straight pg (make sure it’s a clean coil/wick) and you’ll see it’s like vaping air. [disclaimer - this has been my experience. If you try it and find straight pg gives a strong throat hit, let me know]. What it does though is amplify - not just flavors - but the way nic hits your tongue and throat. So yeah, you can use more PG than 50/50. In fact that was quite common in years past before sub-ohm vaping to find 100% PG liquids. Point is if you’re not getting the throat hit you want at 50% PG, chances are raising it won’t help much. Maybe a little.
I’m suspecting you’re not sub-ohm vaping now. Am I right? If you aren’t, and you’re starting out with a base liquid that is 12mg nic, then by the time you add flavors or anything else you’re only reducing the nic content, and honestly nic is where you’re going to find the most throat hit which is why I suggested sub-ohm vaping. Doing that increases the amount of all components per puff as more liquid is being vaporized in the same time period per puff as opposed to a higher ohm, lower power vape. This would be a good solution. A better solution would be to get a stronger nic base which would allow you to have a higher nic content on your finished product.