I've been making my own juice for a while now, and from my experience, the increase in PG is what gives me the harsh hits. When i vape 50/50, I get a sore throat and all my juices taste harsh. When i add in some VG, it goes away.
I know everyones tastes are different, so if increasing your pg doesn't work, try increasing your vg.
to make it easy, if you had a 10ml bottle, adding 1ml of either pg or vg would change your ratio by 10%