Just got my 19mm halflings last Friday and they are working very well. I was boring and got clear tanks both for style I was building and urgency, not wanting to potentially have to wait on ship date with custom colors. I'm sure more orders will be placed from this terminal in the coming weeks.
First cartos ever for me and I really like the performance over my clearos. Felt like I had to almost flood the carto to get the small tank really full, but otherwise followed directions to the letter, fiddled my thingy (a LOT, as per usual) and let them sit for quite some time. Both fired up perfectly and delivered big satisfying vape. Looks like I'll get about 110ish mouth hits per 19mm halfling depending on juice.
Anyway, here to search out process for how folks handle juice changeovers.