Front brake wheel stud/brake drum question

[Ross F-1]

On my 52 F-1, I pulled the front drum off for a check-up. Putting it back on, I realized there were two sets of holes in the drum, both of which work. This is an original Ford-script drum, and AFAIK the hub and studs are also original.

I have always used the conical holes, because that's the way they were when I got it. But using those holes the drum doesn't center on the studs (it does center on the hub). Looking at the tops of the cones, it is clear the wheel or the lug nuts are bearing down on the cones.

If I use the flat holes, the drum just covers the shank of the studs (i.e., looks like that was the intent). The studs center the drum as does the hub.

I have a NAPA drum from the 80's and it has only one set of holes, and they are flat.

I can't think why Ford would make the conical holes unless the same drums were used on some other cars where they were needed. (AFAIK not the case)

Which holes would be correct? My inclination is that it's the flat holes. No guidance in the manuals.