1/2" isn't something I like for any sorta return or waste drain. Plugs up too easily.
3/4" can work if roots aren't involved lol. If you got a RDWC going them you want 2 or 3 inch PVC and bulk heads or if you are feeling lucky uniseals lol.
Generally bigger is always better, to a point anyways. We don't need a 6 inch pipe going into a 5 gallon bucket lol.