Pin bush oil hole. Countersink?

[MBradbury]

Hi,

I am preparing to replace the piston pin bushes, and have a question regarding the oil holes that pass through the con rod and bush. If you examine the oil hole on the original internal bush bore, you will see a slight countersink. You might be able to just make this out on the attached picture. How do you replicate this countersink? The internal bush diameter is only 0.86" and doesn't give much room to get access with a drill. I suppose a follow-up question would be, is the countersink necessary, or will beburring with a bore hone tool suffice?

Thanks in advance.
Mark
1983 911 SC