I did 1/2" due to the size of the outputs on my return pumps. You can't quite see the locline adaptor, other than as a black piece right below the elbows:
(What lookslike a white pipe in the water is actually a reflection of the PVC
That then goes to a locline wye, with each leg going to a locline "hose" to a flare nozzle.
(Only one of the four flare nozzles was installed when I took this shot.)