I'll get my launchpad in a week and wanna prepare a bit

Is it possible to change the size of the scrollable grid in session mode?
I want that the first 4 columns (4x8 pads) of the launchpad are stationary and the other 4 columns move around while pressing left, right, up and down as usual.
The non moving half would get mapped manually to other clips in ableton and should ignore scrolling. But the LED feedback (counting in the beat before clip launch etc.) should still work on both sides. Any idea? I don't wont to map the stationary clips on another user mode, the switching between the modes would make things too tedious.
A side question: is it possible, again in session mode, to re-map the scene launch buttons to other things in ableton without breaking something?