My vote is both. Two 1" returns on sea swirls flanking your overflow (assuming a center overflow on a non-peninsula tank), and a gyre or MP-60 on each end.
just a thought.. has anybody tried using two DC controllable return pumps on anti-sync modes to create surges through each individual output without creating a surge down the overflow? Makes sense to me in theory, but in practice probably quite difficult to dial in, and probably nearly impossible if using a herbie or beananimal