If you can afford to order in quantity and wait a week to get the stuff I think heaven-gifts has the best DK-TAB there is. They sell an 18mg Dekang DK-TAB in 100% VG that's absolutely the best I've had (and is the only juice the spousal unit will vape). $6.50 for a 30ml bottle but they're gonna hit you with $16 for EMS shipping - so ordering in quantity is a good idea.
I have jacked up the nic content of this stuff to 24mg with some 100mg VG and it still tastes great. Highly recommended.
30ml Dekang VG e-juice e-liquid with 17 flavors - Dekang e-juices e-liquids Heaven Gifts
There's only one US vendor I know of that sells this in 30ml bottles but they're $15 each.
30ml eLiquid DK TAB (VG)
I'm almost positive they get this from heaven-gifts so if you want to save a little money your best bet might be to get it from China. I'd suggest getting one bottle from the US and if you like it, buy in bulk from heaven-gifts. That's what we ended up doing.