How to filter 500 RegLibs who voted in 2007 down to 200 for Sunday letter-writing party

After struggling with the fact that my 64-bit Windows 7 likes to run Java in
64-bit mode, and OpenOffice wants to run in 32-bit mode (the solution was to
do the all-inclusive mega-install of OpenOffice -- I'm guessing because it
installs an entirely separate Java Virtual Machine), I finally have filtered
the Master Voter File that Phil gave me Thursday night, based on
Party=Libertarian, Congressional District=8, and 2007/11/06=Voted at Polls
or Voted Absentee, and there were 484 results. The plan for Sunday is to
send 200 letters. Suggestions on the next field(s) to filter on? Here's
the list of fields we can choose from:

voter_id affidavit name_prefix name_suffix name_last name_middle
name_first street type pre_dir house_number house_fraction
apartment_number zip city precinct party reg_date perm_category
military gender language Reg_Type birth_place birth_date Care_Of
mail_street mail_city mail_state mail_zip mail_country phone email
ASSM BART CONG SEN SUPV 11/6/2001 12/11/2001 3/5/2002 11/5/2002
12/10/2002 10/7/2003 11/4/2003 12/9/2003 3/2/2004 11/2/2004 11/8/2005
6/6/2006 11/7/2006 11/6/2007 2/5/2008 4/8/2008 6/3/2008 11/4/2008
5/19/2009 11/3/2009
My initial idea is to further filter by the 2009 election participation.
For instance, if we further filter by the 11/3/09 votes (both at polls and
absentee), the number drops from 484 to 234. Further filtering to the
5/19/09 votes drops it to 187.

I'm emailing Phil my current spreadsheet, but I can do other filters on the
initial 484 based on whatever other fields are needed. Just let me know
ASAP, so I can get it done and back to Phil by Sunday morning.

Hi Phil,

I came to your neighborhood, but there was no parking anywhere, not even a place without cars squeezing past each other to stop for a second. So I will come tomorrow morning (Sunday), hoping all those folks partying tonight will be asleep on Sunday morning.

I am bringing the cover letters. I am assuming you have the petitions that you will send along with the letters.