45ss Con Rod Chamfer

Xmas project
I'm rebuilding a 45 ss and only have one original con rod (no oil holes).

http://www.apba.org/sites/all/files/...TION041013.pdf says "... chamfering the oil holes..." is allowed. Another blog/forum... suggested that without the chamfer the fishing engine rods break.

My question is how big a chamfer and how best to make it. I was thinking about using a dremel with a conical stone, high speed, low pressure and lots of oil to make the surface as smooth (micro crack free as possible).

Any one have experience with this?
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