DIN settings for a smallish girl

So I know my DIN range, but how does weight affect it? I'm like 100 pounds heavier then this girl I'm lending my skis to (they're way to short for me) I like a 9 setting and I'm a tier III skier, My guess is shes tier II and 120 pounds, anyway this is way a rerun but could anyone think up the din setting off the top of their head? I'll search after my homework is done

you need boot-sole length.

then, go here: DIN chart

Thanks thats exactly what I was looking for