My goodness! You've been vaping for 2½ years and this is your first time with cartos?! [It only took me 2 years.;-)]
In my experience, the higher the power, the greater the Rice Krispies effect (snap, crackle, pop). 1.25Ω on 3.7V = 11 watts of power (very high). [NOTE: This assumes that two 2.5Ω coils really do have a net resistance of 1.25Ω. I'm not convinced of that. The two 3.2Ω coils in the "1.6Ω" dual coils do not hit as hard as the 1.7Ω single coil.]
Vapor generation depends not only on the power of the hardware, but also on the e-liquid (e.g., proportion of VG) and the vaping style of the user (e.g., duration and force of the draw).
In this video, pbusardo demonstrates how to fill a cartomizer using the condom method. [He uses the smaller capacity Boge carto, but as he notes in the caption at the 42 second mark this is equally effective with the dual coils. It just takes more juice.]
FYI: The topping off that he demonstrates at the 7 minute mark can be used to fill the carto from scratch. I do it more quickly than he, dripping and turning simultaneously. Doesn't take me long at all even with the 40+ drops needed to file the larger capacity mega dual coils.
After the initial fill, when the vapor and/or flavor start to fade, I top off with about 10 drops right into the drip tip. Yeah, some juice gets into the center hole. Gurgle, shmurgle! It passes.