Thankfully I believe I've seen a single coil version of the flanged carto
What I've found is that I don't see or feel the need for a flange, especially since Smoktech badly screwed up the design of the bottom piece of the DCT tank so the flange on the carto either A) engages very poorly if at all with the molded-in flat spots on the bottom cap, negating much of its purpose (keeping the tank from spinning around the carto upon removal of the tank from the PV/APV), or B) has no chance of engaging since no attempt was even made to mold flat areas into the bottom cap of the tank.
The addition of a trim ring over the eGo threads keeps the tank from sliding down - problem solved. And a carto without a flange allows you to replace the carto even on a full tank by simply sliding a new one in from the top of the tank, which then becomes the bottom of the tank. Coincidentally, I just did it about ten minutes ago when the draw started getting a little hard. Insanely easy, and very convenient. Gotta keep those great vapes going in this war on cigarettes we're fighting. Keep your powder dry, and your cartos moist!
Crystal Clear Vaping has a very good deal on 15-packs of 2.0 and 3.0 ohm single-coil XL stainless steel cartos. They're presented as being Boge's, but the box just says "Atomized Cartridge", and has markings on the side saying "Dekang Inside" and "SGS". (Anyone know if these really are Boge?). At any rate, they work great, with no funny taste.
The 2.0's tend to run a little higher than that - generally around 2.2 - which makes them just about PERFECT. Hands-down the ideal cartomizer to use in a Twist. Single coil, right in the Twist's volt/amp wheelhouse.
Crystal Clear Vaping
$21.70 for 15 - $1.45 each. Pretty tough to beat.