There is no standard dimension for the thickness or more exactly termed, race location as measured from the bottom bracket shell edge as installed.
Stronglight is a bit different from TA or Campagnolo.
Usually the spindle dies first compared to the cups, think less length of the bearing track.
Unless the cups and or spindle is pitted, fresh bearings should get things good to go.
If dead, I think you will most easily end up with a complete alternate bottom bracket.
Veloorange, SKF, Phil Wood, or used from eBay.