Tbh, and I don't mean to come off too harsh, but find that a shame to hear. I would hope making such a bold statement about water cooling vs. air cooling there would have been more evidence based research.
I don't know if it would be unbecoming, it could be done rather nicely concerning a special duct for a radiator. Nonetheless, looking at alternate solutions like proposed in this thread will be left up to others.
It may be a lot of work to research that stuff, but that is better than the sloppy work delivered by LTT on this video.