PITR warm-standby with 8.2 setup questions

I'm trying to get WAL file copying working across two systems. It seems
pretty straightforward to handle this in the "archive_command" of the
primary, in which I am able to copy the files easily to a staging area
for the backup system.

On the backup system, I have the recovery.conf pointing to my script,
but I have a few questions on how that program should behave, and
whether I'd be much wiser to just use pg_standby instead of my own script.

1) I do not want to give the backup PG a file unless it's a "complete"
file. I don't want to give it one that is currently in the middle of
being transferred from the primary to the backup system (or a backup
copy that failed in the middle). Most of my files are 16777216 bytes,
so I initially checked that size. But I found that there are files with
a name like '0000000100000002000000DC.00000020.backup' that is only 272
bytes. Will that file also need to be given to PG recovery, and if so,
how are most determining if a small file is complete or just a partial
from the copy?

2) On the recovery side, the %p and %f values are giving me %p of
'pg_xlog/RECOVERYXLOG' and %f of '0000000100000003000000B1'. Can I
confirm that this means my recover program should find a file named
'0000000100000003000000B1' in my backup system's WAL archive and copy it
to the file named 'pg_xlog/RECOVERYXLOG', or should I put it into
'pg_xlog/0000000100000003000000B1'?

3) On the backup PG, is it correct that I have to remove backup_label,
postmaster.pid and pg_xlog if they are part of the or TAR backup from
the primary's PGDATA area?

Thanks,
David