Thank You guys for all your tips, suggestions, opinions.
Well, my own research led me to conclude something similar to what you siad. In particular Ron, I also read that about the clan tartans, it's kind of ironic. And about your suggestion to look for celtic and germanic tartans I found out that they also had some colours, yellows, light blues, greens.
Another conclusion is that what is possible tha in this time they didn't have is the complicated tartan designs like the cameron of erracht, but they probably had something like this:
So, the colours of celtic and germanic cloth plus this desing, give me a diverse range of colours.
The earthly tones are certainly correct. And now comes the usual dilema: truth or a little twist to give a more beautifull figure? Because this:
Pops out way more than the above....
By the way, is also possible that they already had this desing and colours, or maybe more simple than this (which was my idea), because the codification of designs happened in XVIII century. Repeat codification, which is not creation. So,it's possible. What I'm thinking is a dark red, something more like brick red, not the english red, whith green stipes, making a more simple sett.
See this figures here from pegaso, representing barbarian warrior that have several different colours, and yet are great:
Maybe I go with this simple sett (the first is not so simple, almost burberry's tartan).
Regards
Pedro