I use to have two spray bar returns in my 180gal from 1996 - 2006. When I finally removed them this year and went with the basic open-end pvc on one side of the tank (opposite of side with drains), it greatly improved the surface flow.
This was accomplished by no longer having the pvc spray bars at the water line interfering with the surface water movement thus creating better surface action as well as having the open-end return pvc flowing only horizontally, focused at pushing water along the surface toward the drains. I think this design has greatly helped improve the poor water flow/circulation problems I use to have.
The spray returns were located in the center of the tank and each one originally sprayed vertically. The problem with this was that if any air bubbles were present in the return line they would get pushed downward into the tank and many of the bubbles would attach to corals, liverock, etc. If the spray bars were placed above the water line then I would get too much "splash", which caused a lot of salt build up on top of the tank and a film on the MHs. Because of this I had to lower the spray bars so they sat on the water line. I modified the spray bars so they would also spray horizontal (to help with the air bubble problem). Although the spray was now horizontal and vertical, having the spray bars on the water line caused the surface flow to become interrupted in the center of the tank. Because of this, sometimes a surface film would build up in an area that could not be easily cleared out by the return flow. This was a sign of poor surface movement. This also caused a lot of particles in the water column to not get "caught up" in the upper flow and make their way toward the drains and eventually to the sump/skimmer. To try and help with this I added a maxijet on each end of the tank and pointed the output upwards at the surface to help break up this problem.
What I have done now is instead of trying to use the vertical flow of the spray bars as part of the water circulation in the tank I leave it up to the Tunze PHs to perform this task. With the spray bars removed and the Tunze PHs taking care of the water cuirculation, the primary job of the open-end pvc return is focused on managing the surface flow. I was also able to remove the maxijet "heaters" that were being used to break up the surface water (I say heaters because I only needed the PHs to help address a problem. If I resolved the problem then I wouldn't have the extra heat added to the tank).
If you want to go with spray bars then hopefully by expressing the problems I've encountered it can help you with a design that works well. I dunno, maybe there is a popular design out there that already takes care of these problems.