In a standard length CE2 I've had good luck with all-VG juices. I just have to make sure the gasket that sits on top of the cup is pulled up a hair more than usual. I've had some issues with the XL ones, though, and have to thin the
juice a little bit for best results. I can't speak for CE2
tanks, believe it or not I haven't actually used any of those, yet (a situation I plan to rectify soon). My standard DIY mix, which is what I use most often in CE2s, is about 50% VG and has worked just fine in my experience
I've actually found that filler type cartos work fine with VG as long as you're patient enough to let it all soak in fully. It wicks just fine after that initial filling if you give it enough time to saturate
The same goes for carto
tanks, I've had great results there as long as I fully saturate the carto on the first fill