Drilling main gear axle

I have to drill the u403 brake flanges and main gear axels on my 1990 rv4 kit. Thankfully I have a milling machine as this looks like something that would be easy to mess up. There don't seem to be any dimensions on the plan. So I am assuming this is not critical and I just line up u403 with the inner edge of the axel (where it starts to neck down) and drill inboard of the brake flange in the middle?

Ah ok, the reason nobody has an answer is because the factoy has done it since 1993!!!! Oh well, my kit is older than that so I will have to figure this out. Unless there are some grey haired folks who did this back when GHW Bush was in the White House.

If I recall, my -7A had the hole in the axle but not in the brake flange. I also sometimes suffer from CRS, though.