i went with the 9" version of this on my last build:
https://www.amazon.com/gp/product/B00GB861OY/ref=ox_sc_sfl_title_1?ie=UTF8&psc=1&smid=A67FFQ1POP4BF
the 9" one would light up channel markers for like 2 miles. the 4 rows of LEDs helps it throw (distance) & spill (peripheral) more when compared to a 2 row setup like most light bars. the downside is it sticks up so it can trip you more than the lower 2 row style. i figured either would be a tripping hazard so why not have more light. height never was a negative issue for me.
the LED bar will throw great, but leaves much to be desired when it comes to seeing the banks, even with the 4 row one i had...when it comes to spill, or being able to see the banks, you may want to add something like these, :
https://www.amazon.com/gp/product/B01HT642WY/ref=ox_sc_sfl_title_7?ie=UTF8&psc=1&smid=A12A3GM6KYLIDT
unless it's foggy, i run 30+mph at night, but i also do that w/o any light & only in known waters, the light is just helpful when approaching channel markers & otherwise avoiding obstructions like crab trap buoys. be sure to use common courtesy & turn it off whenever there's another vessel approaching or anywhere near the path of the LED beam.