I think Kara got most of the questions ...
MMA was designed exactly for the reason you want: Practicing at home. Exactly what I do every day.
In addition, MMA has grown up quite a bit and can do a lot of other neat tricks
Have a listen to some of the sample stuff on the mellowood site as well as here.
As to specifying tracks to use, I think you'll find that you don't really need this feature. It seems to work most of the time "out of the box" with the auto allocations. But, if you need to: yes you can.
And do shout if you have more questions.