By the way i’d have to point one important thing out.
All the lumens and throw specs listed in here would be be available in TURBO mode only.
That means in small and light lights (what we call pocket rockets), on the extremely powerful lights listed here, max output would be available for a very short 30-60 seconds burst at most. Double that in winter perhaps? Recovery times are also not gonna take less than 5 minutes, unless you splash it with water.
On less powerful lights, eg the Convoy L6, that effect is going to be less noticeable, you might get 3 minutes in Turbo before ramp down due to temp regulation or your hands give up. Since you’ll be mounting it on your kayak it’d be via regulation. If there is no temp regulation or it isn’t working well, you might have a dead light soon after forgetting to turn it down after a few times.
Take for example the Convoy L6 and Haikelite MT09R, both are of the same weight. One is like 20k lumens with each XHP70.2 driven to close to 7k lumens. The other is a single XHP 70.2 driven to just under 4k lumens. In reality, after the initial turbo burst on the MT09R, you’d need to wait out for quite a while for it to cool down first before attempting the burst. You’d need to search the reviews and see how long it’d take for it to cool down say 15 deg C before it’s good to attempt another turbo burst.