If possible I would put the injectors back in place and try to run the engine, while spraying throttle cleaner into air intake (throttle body). It will clean alot inside the engine while pushing it out with exhaust. I would repeat that process many times (maybe 3-4 times) and see what I get. If I am not satisfied with the result, then I would remove the engine head and clean it manually. I think physically trying to remove the debris from injector ports will make things much worse. There is still an option to decarbonize the engine cylinders through oil system. I wouldnt rule out that option either.