The actual Battle of Surigao Strait, which I'm assuming you're emulating here (though not necessarily trying to accurately recreate), took place at night. You might consider dialing down the light to a twilight level to simulate this. It'll also result in shorter engagement ranges, I suspect. Also, the opening attacks were conducted by PT boats. You might consider allowing each side a limited number of PT's to launch early in the scenario (even though only the US had them present at the actual battle), and maybe also at the end, once one or both sides have lost all their capital ships. I don't know if you're fleets are already created in the terrain, but if not, I'd recommend creating them with the capital ships line-astern, with DDs flanking both sides. Also, it would be great (if it's do-able) to have some sea level cloud banks dotted around, to simulate patches of fog and/or isolated rain squalls. Playing hide-n-seek in the fog/squalls would add an interesting dimension to the battle. Finally, you might add the objective of requiring at least one Japanese capital ship to reach a certain location on the map, which would be conveniently on the other side of the American fleet, to insure battle is joined. This would simulate the Japanese objective to reach Leyte Gulf and the American beach head.
