Disklavier

I have just one week with my MPX1Z DISKLAVIER and had been testing 
it just to figure out how to use it with MIDI.
 
Every ting is working fine but I have some minor problems so I need 
advice.
 
I'll post some messages whit this subject to keep a separate track 
of each one.
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My midi files are volume and velocity balanced to sound fine in my 
PC, but when I play them, untouched, in the Disklavier
(Tracks 1 2 for piano parts), the piano sounds really loud and the 
XG tone generator sounds with a low volume.
 
I have edited the tracks and noted that the velocity parameter of 
each note in the piano tracks should be between 40 and 70 to sound 
nice, and the XG tracks should be between 90 and 127 just to sound, 
the volume should be 90 to 127 also.
 
The questions are:
Is this a normal behavior?
Does the Disklavier respond to the volume control?
Is there in the web a page with tips or tutorials about arranging 
midi for the Disklavier?
Have some one some other tips on this.
 
Tanks