Your results and mine are much different. On an eGo regulated battery ~3.2v, there is very little vapor. On an unregulated 3.7v
device, there is some vapor, but still not much. Even with a 50/50
juice at 4.2v, I did not find the triples to be all that productive. At 4.8 and on a 5.0v regulated, they work great.
7.4 volts is too hot for me, but 6.0v is just fine.
You should really consider using a derlin drip tip on hot devices like these. I did not find the vapor to be too hot for my mouth at 6.0v, but the carto tube does get scorching hot even with a few drags at 5.0v. A derlin drip tip will mitigate your discomfort for sure.
Also, taking a 5 second drag is the only way to get any vapor out of these at 3.2 and 3.7, but I take a much shorter drag at 5.0v and above because such a long drag just isn't necessary. That's the beauty of the multi-coil cartos. You can take a short drag like an analog and it just isn't necessary to draw on it so long. - If you continue to use multi-
coils, you'll keep them cooler and still get very satisfying vapor with a much shorter draw.