Tank dimensions help. If it is a standard 48x18x23 design, I would suggest at opposite ends, facing each other. The cycle is more flexible, but I personally like a lot of variable turbulence. Be careful of creating a traveling wave from end to end. Those have been known to cause seams to fail. Or slosh water over the sides. The MP40’s can move some water!
fwiw,
The shallow front to back dimension may limit your reef size & coral placement some.