See comments below
In short gs_6.x: it has some issues for pdf generation
(math and other font problems which surface when other people try
to print it under Windows)
> I now installed gs_6.01 (which is quite a hard work for a
>non-programmer) and the pdf files are nicely small. Also the text
>charakters are looking good. Is it really not recomendable to use
>the latest gs_7.0 or the gs_6.5?
I use both 6.01 and 6.5 (6.5 with a small patch which I can send you
privately, or wait a little for the 6.51 release) and did not encounter
major problems except for the minus symbol problem below.
I did not try gs_7.0 yet.
> There is one strange thing left. When I export the document from
>Lyx to a ps-file and then do ps2pdf all the minus symbols from math
>mode are gone?? When I export from Lyx a DVI-file and then do
>"dvips -Ppdf" and after that ps2pdf everything seems to be OK.
I noticed the same problem when printing gs6.x generated pdf files to
postscript and non-postscript printers with acrobat reader in Windows.
The minus symbols were present on-screen though! No problems with
printing to postscript printers under Linux (from Acrobat reader).
> So my question is how can I specifie this "-Ppdf" inside Lyx?
I added this option in LyX 1.1.6fix2 preferences
(Converters->Converters), with LyX 1.1.5fix1 this should be possible
by defining \dvi_to_ps_command "dvips -Ppdf" in ~/.lyx/lyxrc
With this change, other problems are introduced! For example,
fi character sequences in normal text became a pound sterling sign ????
Conclusion: do not use gs_6.x for distributing LyX generated
(through ps2pdf) acrobat documents
Hth
Paul