PG is usually listed first
100% PG will let through all of the TH but can be harsh - makes my tongue and throat sore
I never tried 90pg/10vg
80pg/20vg smooths it out a bit, adds more visible vapor
I usually vape 70/30
The flavor also has a lot to do with TH. Some tobacco flavors have more TH than others. Some fruit and desserty flavors have little TH, but flavors with spices, ginger, mint, rum, and other things like that often have extra TH.
And there is an additive for TH called Qhit - I think they have it at One StopDIYShop
You can also buy a (black ground) Pepper ejuice at FreedomSmokeUSA which can add TH