I generally buy juices from juice makers, not hardware vendors. The Dekang juices are cheap Chinese juices - some of the tobaccos are OK. if they have any High Caliber juices - those are supposed to be good but vendors are not interested in ordering the quantities necessary to get them so the choices are sparse.
I do get my drip tips at LiteCigUSA.net - great selection. Those new swirl ones are a tight fit in everything I have (and the fancy acrylic ones found elsewhere are worse). I usually use the clear colored plastic and black delrin. I use them for dripping (on atomizer + manual battery) and as comfortable mouthpieces on cartos.
In simple stuffing cartomizers I use PG w/ 20% or less VG and a couple of Vapor4Life WOW juices (those are thin and those I've tried have been pretty clear). I avoid juices that drop a lot of flavoring sediment in the carto stuffing.