KPHW is running 74 KW from 2500 feet atop Wiliwilinui. But KRTR at 96.3 is also running 74 KW on the same antenna from the same location. So the signals should be identical. But that is Oahu, and if you are talking about the entire state, the stations with the best overall coverage (a combination of power and height) would be KKUA and KIPM on Maui. KKUA is running 56 KW from nearly 4500 feet above sea level, and KIPM is at 62 KW from the same non-directional antenna.
If we are talking about coverage over actual listeners, then the Oahu stations are the clear winners, simply because Oahu has more people. But either Wiliwilinui or Ulupalakua (on Maui) are not perfect and cannot reach everything, despite the heights of their towers. The adjacent mountains are higher or at least cause signal shadows.