I have recently tried (and liked) using KR808 cartomizers on my Omega... WOW. I popped the top out of the cartomizer, stuck in the black plastic drip tip. Put the cartomizer on the 510-901 adapter and am using 2 batts @ 3v. Great vapor, nice TH, and easy to refill.
I tried the direct dripping but didn't like the metalic taste the 901HV or the 510 LR and 901LR atomizers have while dripping. Using several cartridge mods was still messy, and I can only fill 3-8 drops, which at 6V vapes quickly. The cartomizer holds the most drops, vapes nicely and with the drip tip, is easy to refill.