lighter cloth vs heavy?

What´s the difference between using multiple layers of lighter cloth vs using single layer of heavier cloth? thanks in advance

Hey affe, There are many more details than this single one of course. Correct me if I’m wrong. Two layers of 4oz laminates 17% heavier than a single layer of 6oz and is considerably stronger. The I don’t know the exact relative difference in strength comparison. How about it experts? Mahalo, Rich