Both have pretty tight windows of power (watts) because of the ohms, airflow and actual construction. They were designed 1.5-2 years ago. The power that is being used is quick to over-power them.
When I used the PT2s, I sat between 7-9 watts. I added the air flow attachment and that would let me go up to maybe 11 watts before it got hot (for me). Even the drip tip is not fabricated to disperse/reduce heat.
The Nautiluses, I had about 6 of them, did better for flavor and that was really the "thing" at the time. Cloud-making, as we see today, just wasn't part of the design. But their construction let me go a little higher in power if I wanted.
Both of them, using stock coils at the time, was limiting. Rebuilding the coils or using a newer coil insert may change things, but not by much.
Your Kanger Ipow is also a limiter, but, not as much compared to the PT2/Nauties, in my mind having owned several mini-tube mods.
To determine your upper limit, for you, set you power low and slowly raise it until flavor drops off and heat gets tooo hot.
Your set-up is plenty to keep you from smoking. Flavor and clouds just shouldn't be expected. To go in that direction means education/understanding and money.
This forum is used mostly by hobbyists, so you would read as much about those using set-ups like yours very much. They got their set-up, are happy, and getting off cigs.