Hash marks would be fine for bins, but kill marks might be a bit much. Good for TIE pilots, but for troopers? Whatever we use, it should have delineations of 5, 10, 50, 100, etc.
Accuracy jokes aside, we're not talking about hitting anything except the number of troops under one's belt.
Are Roman numerals used in canon? Even if not, we could use them for major troop milestones, like Albin has done with membership anniversary coins.
Or we could just mike vinyl stickers for totes, cars, etc. when troopers