Non Siphon Drain - Straight Down or Slight Angle

[Harry Muscle]

I'm running a Glass Holes 700gph overflow and I'm wondering if the drain (non siphon) should be a perfectly vertical drop straight to the sump or if I should put a bit of an angle on the drain line? Which would produce less noise and allow more water flow? I'm planning on about 400gph of flow and the drain is 1.5".

Thanks,
Harry