I am running a c2c overflow and love it. Running about 700-800GPH with 1 1" drain spit to 2 bulkheads. I run Herbie style, with 3 1" bulkheads in my overflow. the 2 on the ends are T'd together to a common 1" drain into the sump, the middle 3rd one is the emergency overflow. Handles the flow nicely. And the surface skimming is awesome with the c2c. just a thin film flows over the wier.
Here's a back pic of the plumbing. you can see the overflow on the side of the tank. Its a full length, 7" wide piece siliconed at an angle for the overflow.
