easier for plumbing as the pipe work is smaller where the gates come off the manifold... you can run a single "larger" gate somewhere in the 50mm range and do something like this:
I personally run 875cc Siemen DEKA IV top feed stainless steel injectors and my duty cycle in hitting 90% (or so) already.. I'm going to re-tune the car soon as it has a new turbo setup and I'm pretty confident I'll run out of injector pretty soon... but saying that, because they're modern injectors I'm able to bump the base pressure without any real issue.
New modern injectors are very linear, meaning they won't fall off like your conventional injectors and give you poor economy and/or idle with low pulse widths.
Oh.. that turbo is a little overkill for 300kW not to mention will be on the laggy side.. how big is the compressor? 76mm or 82mm?