You can reduce the shells to fit inside the box without losing any texture quality. The frame signifies the area which would be rendered if you do a render to texture/render UV wires. You would choose the size of your texture in your chosen texture software. If you plan on doing a render to texture with your chosen UV…
This is the nature of unique texture UVs. The preview checker is not indicative of the pixel sizes, unless you're using a 16x16 texture! If not rendering for game use, you could use a variety of techniques, like procedural texturing, and/or UDIM…
The thing is i am already using Mirrored Uv´s and overlapping uv´s and i used the normalize uv´s option in TexTools which gives me this big uv shells in the first place. Hope i didnt missunderstand anything but doesnt lowering the uv shell size mean bulkier textures or lower res textures?
Can i keep my uv shells this big somehow or enlarge the black boundary thingy in any way? Im asking because if i do the following am i not losing a lot of texture quality later on? Thank you in advance! :)