Is your Clover always too hot on the High setting? I’ve found that mine can get too hot if I leave it sitting on a stand for a while, but then if I rub it on some wood or something for a few seconds before using it, it cools to the right temperature. I think part of the problem is that the stand holds it with the tip slightly elevated, so hot air rises towards the tip, keeping it slightly hotter than it would be if the stand held it tip-down. I might experiment with a new stand to see if this changes anything.
Have you tried boosting the “Mid” temperature by wrapping a bit of aluminum foil around the shaft?
The Top-Flight sealing iron is nice because its temperature is adjusted by a dial, so it can be fine-tuned, but it’s really too wide for making packrafts so I don’t recommend it. I built my first packraft with it, but it was painfully slow because I couldn’t use the flat part of the iron (too wide), just the tip and the edges. I have the temperature set to “3” for sealing the fabrics I offer, though some other TPU-coated fabrics melt at this temperature. The videos that feature this iron were shot before I got the Clover.