I believe 3x250w would handle your needs very well, keep the SPS
in the upper half of the tank which is probably the most popular place for them anyway.
If I was doing this tank, I would only run a small amount of water down through the overflows into the sump to help keep things quiet. Enough to feed the skimmer area well without creating a jacuzzi. Then I would drill the back for a closed loop using one large or two smaller external pumps into a manifold with several outputs into the tank.