the master volume is fine as long as its below 0db.
and theres a smaller menu thats hard to see and you need to drag up just under(maybe above) the piano roll - atleast in logic 8, here u can draw in pitch automation as usual.
when hi-passing breaks, it depends what frequencies you already have in your tune...for each element/track you want it to have its own range of frequencies. of course you can have instruments overlapping but too much of a certain frequency will just cause your sounds to be muffled.
so if your using a break to fill out your drums (using the cymbals etc.) then just use a spectrum analyser and see where you are missing frequencies and eq the break to fill that hole.
hope that helped a bit im not overly knowledgable so im sure someone will be able to explain better (or more correct...)
