Cartos are a little bit different because the coil is surrounded by a sock which is surrounded by filler which is full of juice, so the coil is fed from all 360° and there's no real wick to speak of. Thicker juices do a little bit better in cartos because of this. CE2s pull the juice in through the wick from outside the cup, and the coil is wrapped around the cup so it relies more on the absorbency of the wick and its ability to soak up juice at a pace that's fast enough to feed the coil enough juice to keep pumping out vapor at your current voltage level. The Fluxomizer Deluxes have a pretty good wick but they have their limits. You can help the limits along with some fluffing -- or if you are ridiculously ambitious, replacing the wick with SS mesh, which also requires replacing the coil, so you might as well stick some Kanthal wire in there for robustness.

(Yes, I've thought about this, and yes, I'll probably be trying it at least once.

)