Why did Gene wear Finny's clothes?

When Gene dresses in Finny's clothes, he assumes Finny's look and manner of confidence, thinking that it suits him and describes who he has become; this is also ironic, since Gene's insecurity defines his differences from Finny, and since the clothes and the look belie Gene's character and his true feelings. However, the growing resemblance between Gene and Finny not only shows their differences, but also foreshadows their becoming like one person.