I've gone through a few iterations of UI loss markers over the years.
First I started with 1 marker per unit, with a numbered loss marker on each corner of the stand. The stand is just rotated to show the UI loss on the right front. This worked well, requiring only 1 stand to be removed and replaced with the loss marker, but players could confuse which number was the actual loss number. Also, the big white numbers detracted from the appearance of it all.
The second iteration was to use casualty figures and eliminate the numbers. This looked great, but had a couple of problems. For 3 or 4 UI loss, the system required 2 stands to be removed. As I use 4 stand infantry units, that meant that 1/2 of the unit was removed and replaced with casualty stands. Also, I didn't create specific artillery and cavalry casualty markers, so sometimes it was a bit odd seeing infantry casualties on a cavalry unit.