>>532776867
Yeah, you open textools and go to the face you use. Check the textures and export to png or whatever. Then just make whatever changes you want, replace the texture file with the one you edited and either just load XIV with those changes (probably don't want to do that) or create a mod from items to load with Penumbra. May take some trial and error to get it looking just how you want but it's quite a simple process.
One you have the mod loaded in Penumbra, you could also just use advanced editing and switch out textures on the fly so you don't have to create several different mods to compare your attempts