Depends, various brand names will be varying in viscosity.
ECOpure VG does not need to be dilluted, for me, it's aqueous VG and works great in my 801 carts with no added water. For Flavoring I use tobacco absolute cut with ethanol, so at 20% flavor it is perfect viscosity. I would compute it to be about 5% of total volume added liquid. Vapor volume is excellent. Flavors taste great, and it vaporizes very very cleanly in the atomizer. I cannot use even a pinch of PG, so this works best for me.