Anyone tried to move/resize model textures for FiveM?

I am currently trying to optimize the clothing pack for a server I am on, and I have discovered that some of the items have texture sizes that are FAR out of proportion to the item itself. The ones that are using all the space but are just larger than needed are easy. I found the tools to handle that. It’s the ones where the texture file is huge, but only a tiny portion of it is used that are giving me trouble.

I have done textures before, and I have done modeling before, but putting them together in a new-to-me program (3DS Max) is always a pain in the rear. So, hoping someone else has some advice on either how to go about this or why it is a hellscape I should never attempt to enter. Is it just a matter of finding the right origin and scale, or…?