Yes, I do like the 3.5ml Smoktech DCT tanks themselves. it's the Smoktech cartos I can do without until they fix the stinky, make you juice taste like used gym socks problem.
The cartos that fit that tank are "XL" sized, about 44.4mm from flange to drip tip end, and about 49.4mm overall. I don't know of any manufacturer other than Smoktech that makes the flanged ones, but you really don't need the flanges if you either a) have a PV with recessed female threads or b) use a trim cone/plinth on ones that don't, so the tank sits on that instead of sliding down any.
Lastly, just make site you give the carto plenty of time to stabilize (absorb ALL the juice it can), and put juice right into the top of it until it finally begins to just barely pool up on the surface of the polyfill. And the juice level going down is perfectly normal, and simply the result of the juice going into the hole or holes in the carto.
And really lastly, some of my juices flow just fine into the three tiny holes on a Smoktech single coil, and some don't, which as you say will require a little slotting with the Dremel. I use their 1mm thick abrasive cut-off wheel, and cut just until a slot no bigger than 1/8" long appears. The only time I cut to slots, it flooded, just as PBusardo had happen and warned about in his slotting vid.
