Hiding staffs with rests

[Bertalan Fodor]

Hello,

I have two problems (Lily 2.2.0):

1. 

\partial 4*1 R2. 

doesn't seem to work.

2. 

I have two staffs in a choir staff. The second has 16 measures rest. I want
to hide the second staff in the systems that would only contain rests, but
in the system when second staff comes in I want the empty measures to
contain rest. So something like this:

1-notes-notes-notes

1-notes-notes-notes

1-notes-notes-notes
2-rest--rest--notes

I tried \set Score.skipBars = ##t, but that didn't hide the staff in the
first two systems.

Thank you in advance,

Bert