You mentioned a carto tank. Is that a clearomizer? Clearomizers wick through long strands of fiber rope and VG doesn't soak them as well as PG. You might find that a juice at 70pg/30vg might wick better. Also, periodically holding the tank level allows the juice to flow toward the bowl and wet the wicks more efficiently.
If it's a carto with polyfill, like a Boge, they don't perform well at all with thick juices. I don't particularly like 100% PG, but I've found some PG juices taste good in my Boges and don't knock a hole in my throat with the harshness.
I like Awesome Vapor Camel and Virginia for tobacco flavors that tastes good with mild TH.