I'd say a headset cup or cone is more likely to be loaded across its entire face.

If the pits on the right of the spindle are turned around to face UP instead of DOWN when you are pedaling, there's no load on them. When you pedal the LEFT side, the pits on the RIGHT side face down, but the spindle is being levered so the RIGHT side is pressing UP.

However, it may still be a bad idea because Sheldon thought English spindles could be adapted to French frames and cups. If the old French spindle pits even a little more, the hard particles that crumble out can then ruin the cups, then you won't be able to rebuild your BB with an English spindle. So it depends if you're going to keep using the old cups, or just want to squeeze a bit more life out of them to see if you like the bike before spending $50 on a new VO bottom bracket.