Lazer RF performance for small non reflective targets

[PhilSchmidt]

What specs are most important to allow a RF to perform best on small non reflective targets in the 400 to 600 yard range? I know that is a stretch for any rangefinder. As far as accuracy on small targets I believe beam divergence is a bid deal t but what about power? I see the Leica has a vertical beam divergence of only .5 while the Kilo 2000 is listed at 1.4 which would not be as good on smaller targets.