thank you all!
I like to do my models in monochrome red, yellow or blue : it is a bit an extreme choice, but I find that it underlines the lines and shapes. So it is just a matter of style, but I certainly recognize the ptential of decals, especially with creative patterns as you do, andonio64 : a giraffe patterns would be great :) (it has been done in the real world actually, for the Sikorsky S-38, and there is a rein kit with corresponding decal sheet, very impressive)