Hi, Roberto!
you have made a nice soundfont.
like Steven i'm using qsynth but my keyboard is a m-audio keyrig 49,
which is a very basic model. it only has 3 buttons! :0(
i also find that not enough velocity range is given to the quiet layers,
even with a sensitive touch i reach the fortissimo layer quite easily.
it also is not quite as loud at fortissimo as other soundfonts in my
collection.
i hope this information is useful to you.
keep up the good work :-)
best wishes, G.