Thanks Karyuu, will try to follow your advices

Btw, i thought about what you said for the UV map wasting space, thus lower resolution, but i couldn't manage to obtain a decent UV map (one that doesn't waste space, that is). I will try again, maybe it will work this time

And for the overlapping, i did not know it was possible, that seems really something interesting, thank you

P.S : i didn't find how to do the overlapping thingy, if you could tell me how to do it, or give me a link for a guide, it would be cool