Each point of perception increase your chances to find something by 10% and luck give extra 3-30% chances. Now you may select PER 7 and LUC 10 to have the same chances as PER 10 and LUC 1. With PER 6 and LUC 5 you have 60+15=75% chances. Luck will work as bonus to every action so its worth to select it. Amount of items depend on place where you search and will be randomly. For example junk: in boxes 1-1 in car wrecks 1-3 junk on table in workshop 1-5. Or food in boxes 1-1 in fridge 1-3. I think this system is best because simple and universal. Each action will test one stat plus luck bonus. Also am think about made very bad consequences when select "gifted"