Lead in angle on fuel rail for injectors?

[leeroy_25]

I have modded my primary fuel rail to take 850cc injectors and just noticed that there needs to be a lead in angle at the top of the injector hole to allow the injector body to sit down and locate correctly. Can anyone who has done this before let me know the angle I need to machine in.. It looks like a 30deg (60deg) lead to me? wondered if it is that critical or if a standard 45deg countersink tool would work to allow the injector to sit fully home?
Thank you
Lee