I would have never imagined this would have become the best kept secret in SPS keeping but it did.
Nothing beats a properly sized/powered/reflected MH with LED supplement for large or cube footprints.
MH is a growth engine and LED is a color engine.
I doubt OP is open to MH though.
I would prob go with 3 Prime 16 HD. That would light the central band of the tank well for Acropora and the 3rd unit would let you run at lower power and minimize shadows/drop off.
The hybrid t5 units are an good option as well. I think you'd be pleased with 2x 16 hd's in a 24" hybrid housing. Would get better growth without sacrificing much color vs all primes.