... so I donate my size 2 and 4 clothes, but most people in need aren't size 2 and 4.

a) So are people in need who are in size 2 and 4 better clothed then people in larger sizes?
b) So are people in need who are not size 2 or 4 benefit from the sales of my clothes?

I am just looking at a big bag of donations and not knowing what I should do with them; donate them to a place that will get money from my donation (Salvation Army) vs. a place that will get my clothes (Homeless Shelter/Hospital).