THe issue really isn't where, how much flow, is it primarily very laminar. The goal is to move as much water as possible without blasting any direct flow at any of the tissue. If the flow doesn't slough off the tissue, you may get algae growth over the point of impact.
Have you ever checked out any of the Maxi jet modifications? Great way to increase your flow in a cheap way. Check out reef chili's web site for more information or Melevsreef.com for an alternative and simpler modification.