Problems with drum score

[Cameron]

Hi folks,

I'm typesetting a drumkit part. I've had a few problems that are 
stumping me.

I'm using LilyPond 2.2.5 on GNU/Linux.

1) Grace notes aren't timed properly. They print properly---they appear 
with smaller font and have slurs and strokes where appropriate. However, 
they affect the timing of the rest of the piece. Is there a Proper Way 
to use slurs in drum music?

2) Making 'chords' out of drum notes works fine. For example, I can 
write <cymc8 sn> and I will get a cymbal and a snare playing at the same 
time. However, if I try <cymc16 sn> I get the message:

error: syntax error, unexpected UNSIGNED, expecting NOTENAME_PITCH or 
DRUM_PITCH or '>':
                | < cymc1 
        				6 sn16 > sn [more music]

I have a few more questions as well, but these are the main ones at the 
moment. Any help would be greatly appreciated!

Cameron