On our first-gen build, we are running the 034 Motorsports secondary injection system, spraying a set of EV1 injectors down through the plenum. The primary injectors are Honda S2000.
All suction hoses are -8, as are the lines through the filter and to the Y block. At the Y, two -6 lines run to the two fuel rails. -6 runs back out of the rails and to the regulator, and then returns to the tank.
-8 out of tank
Secondary injectors installation
Here is a quick MS Paint sketch of how we did things: