OK. I got the 1.2 ohm coils in today. Here are my thoughts...
They are TONS better than the older 1.5 ohm coils. First, as suspected, these are a single coil, vertical solution. Also, the wicking channels have been opened slightly... I suspect there's about 40-50% more surface area for pulling juice into the atomizer. Air flow is MAYBE a bit better due to the vertical orientation of the coil. That's to be expected... these coils have the same air flow bottlenecks at the base and head of the coil head. Cotton? Yep. Works. Tastes better. 1.2 ohms? Yep. The coils I installed into my MS and my M tanks both read 1.22 to 1.26 ohms, depending on how the stars align at that particular moment. As expected, these do handle wattage a ton better than the dual 3.0 ohm coils in the old atomizers.
With all of these improvements (mainly the juice channels and the single coil), these work as advertised. On my SX Mini M class in wattage mode, I had no issues achieving the advertised 30 watt limit... even with max VG. In fact, 32-34 watts is quite doable, consistently. And quite hot. 20-25 watts is a comfortable range to me, but if you so choose, rock 30 watts on these all day long and have a nice hot vape. No ideas yet as to coil life... these are literally only a few hours old.
On my stealthy little iStick Mini 20 watt, I'm pushing the full 20 watt limit of the mod, and this tank actually chucks some impressive clouds at that range. Expect juice to deplete more quickly, though. The vaping gods don't give you something for nothing. That said, the 2.5-3.0 ml capacity of the MS tank is plenty to last a while and the 4.0-4.5 ml capacity of the M tank works out really well for these coils.
Overall, I'm quite impressed with these coils... I'd be hard pressed to rebuild these any better, honestly. But, if I can rebuild them to the same quality, that's good enough for me since it'll save me some scratch.
I plan to record a combination video review of the iStick Mini 20 watt, the GS Air MS, and these new 1.2 ohm organic cotton GS Air coils some time in the next week or so. I'll post it on Youtube and post a link in this thread.