That injector setup is pretty cool, the only thing I would watch for is fuel pooling/dribbling at low air velocities since its looks like its parallel to the ground.
The butterfly will go upstream of the injector right?
I think kawasaki did a dual injector setup on one of their newer dirt bikes kind of similar to how you have that injector placed. It used a standard port injector and then a second one that fired further up the intake plenum.
I always wondered if you could use the injector to accelerate the air in the port if you jacked the fuel pressure way up.