Some rabbonim are wearing really long and large talith katan. For example Rav Shmuel Auerbach shlita (picture below). Rav Elyashiv ztl used to wear a very long one too. Which shita are they ...
A theoretical question: If a young person (a boy for example that is 13 yrs old) that happens to be very short (not because of any physical disability) wears a normal size tallis katan it will be very ...