I got one of these today. I pulled out the 1.5 ohm carto to replace it with a 2.5 ohm Smok Tech tank carto (same carto with one hole and flange) for use on my VV box mod.
I lubed up the inner o-rings on both the top and bottom caps with some 100% VG. Both caps have inner o-rings, by the way. Even though I was trying to be careful, I shaved a little sliver off the inner o-ring in the bottom cap when I pushed the new carto through. I pulled the carto back out and put on a tapered delrin drip tip and reinserted it. That seemed to work better.
This is a pretty decent inexpensive no frills carto tank. I used to think these XL dual coil cartos were worthless in carto tanks, but Smok Tech got it right with the one small hole and the flange on the bottom.