The "-charset" parameter currently only affects the body.
I think you should use it for everything else as well (e.g. the subject and from/to display names).
Right now, "-charset Windows-1255" would create something like the following:
I don't know if RFC allows it or not, but I think you should respect our choice for "-charset".
Besides, not sticking to one charset might confuse some servers and cause them to display Gibberish.