The answer is subjective to the build you use and your own personal tastes.
1) Single Coil: In this mode you reduce the chamber size using the ceremic block. The combination of the reduced chamber plus the higher resistance will yield a warmer vape, and inherently flavourful.
2) Dual Coils: Means you vaporise more liquid at any given time, giving you the ability to vape more in one puff. This implies you ought to get more flavour in one hit; however, due to the increased chamber size and air flow, the vape will be cooler, and inherently you'll find your vaping at higher watts.
This is an age old debate. In my case, and keeping within the context, I have had my Avo 22 for months, which I have been running with a single spaced clapton build (ohms out to 0.62) and 9mg e-liquid (steeped 5 months) at 45.6w. I've had my Avo 24 for a month and I've been using it with dual twisted wire (ohms out to 0.55) and 6mg e-liquid (steeped 3 months) at 66.6w. As you can see there are a lot of discrepancies between the two, but if I had to choose, I would say I'm getting a warmer flavourful vape from the Avo 22's single coil build. But realistically, this calls for a more compatible comparison, which I intend to do sometime in the future.
Try it out for youself. It's always to fun learn and customise your vape, when you have time.
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