High percentage VG juice can have wicking problem in the CE2's.
The trick is to vape the ecig horizontally or pointing upwards, this will allow the juice to absorb closer to the cup.
2.8ohm is good enough for a 3.7v device. You could try the 3.0ohm CE2's so avoid vaporizing the juice too quickly, but I don't think it makes that much difference.
Wicking can also be improved by cutting angles off the wick gaps on the third ring (the ring that sits on the cup).
If all the work involved in getting the CE2's to work properly becomes tiresome (I was fed up with them after 6 months), then perhaps try the new G4 carto's.
I've been using the G4's for a week and they are quite good. They are also very simple to refill, just remove the mouthpiece, fill from the bottle, then reinsert the mouthpiece. It takes about 5 seconds to refill and there are no rings/seals/wicking to worry about.
The CE2's do have warm vapor which I like, but I was willing to trade that for simplicity.