Sorry, I don't see any coil specs thus far in the thread, other than the wire that you have.
Running in TC mode is completely up to the user and their preferences. I personally use SS316L wire, in all different sizes and coil builds. I personally do not like TC mode in any of them due to the "cut off" that seems to happen when the temp hits the setting applied, which is exactly how it is supposed to work by design, so it's not a fault of TC mode.
With that said, I'm not against TC mode on devices. I just purchased a Hohm Wrecker G2 that does TC with Kathal wire, so I'm still in the investigative phases of TC workings.
Being that you have 2500mAh batteries and not 3000mAh batteries (Samsung 30Q are quite nice in the Alien MODs), I personally would try to keep it to a mid-range Ω coil (somewhere between .7Ω and .5Ω) just to help conserve battery drain.
Here may be decent build for that dual coil RDA
http://www.steam-engine.org/coil.html?mat=ss316l&s=dp&r=0.3&hf=250&awg=26&id=2.5
SS316L Dual Coil >> 2.5mm ID / .6Ω p/coil (.3Ω total) / Heat index @ 250 would be approx 65-70W power.
So in TC mode, I would set it to 75W(hard mode) and set the temp to about 430 - 470F depending on your heat tolleration.