Hi Avarcon,
from the pdf I cannot understand anything
for me two midi files if I play them on my keyboard:
a)The "Concert Grand" midi is using the "Piano" voice in GM&GX folder.
reverb 16,EQ LOW -12.touch button on and probably sustain button on(or sustain pedal).
Also if you wach the score pattern you will see that is hitting 7 keys at the same time.
It is not by accident that way.Neither that is a small piece of music.
If you can play like this you will get that sound.
b)The "Grand Piano" midi is using the "Live!Grandpiano" voice.
reverb 20,EQ HIGH+32,EQ LOW +44,touch button and probably sustain button on(or sustain pedal).
I can't see what other effects maybe in the voices from the mixer menu,
but I guess for the piano voice you should use some reverb and also some release or sustain if it is a slow piece of music in order the sounds to fade away smoothly and not like you are playing a fast piece of music on a HonkyTonk piano.
On the other hand if you use too much release or sustain in a fast piece of music the sounds of the notes will mess up one over the other.