I have two MP10s facing directly at my mag, 100% power, long pulse reef mode set to it's shortest duration. The nem get 2 seconds of high flow from each direction (two adjacent sides, tank is a cube) and then again from the kick back current flowing around the aquarium.
You really want your mags tentacles swaying every which way, ie random. You want enough flow to really move them around, bending/pushing them completely over, ie high flow.
I aim one of my MP10s so the water flow hits the underside of the nem, the other pushes flow at the tentacles, just slight above mid nem.
It must like this flow, and the lighting, as it hasn't moved from day one.
Hope this helps.