@Mike: So far, I haven't found clearly better strings in the Motif libraries. But I still haven't tried the Motif XS Symphonic strings (400MB). The Garritan section has a good depth, but has a slightly strange vibrato in the upper range and a synthetic touch in some low keys. I get best results combining them with the Motif section strings. But the Integra's are still better all in all.

I am thinking about making a second version just with the Roland SRX 06 Big Strings, which are the lushest strings I know.
Here is an example of them, compared to the Motif large strings:
https://soundcloud.com/rorosetree/roland-srx-06-big-strings.