Please don't use DCC on your KR808 battery. It won't be able to handle the amps that those cartos need in order to operate. I would suggest using some VOLT, V4L, G6, and any other gen 2 KR808 cartos. They'll work with your battery.
VG juices aren't good for cartos but, AVE juices do pretty well. You just have to remember to take your time filling it. Also give it a little break for the carto to re-wick and you should be fine. Just remember to top if off pretty often when you notice a decrease in flavor.