Seeking for vacuum advise

Hello,

We are using postgres for one of our application. Currently using
Postgres 8.3 with CentOS 5.3 x86_64

We are using inherited tables. Base table has 3 columns:
entry_date timestamp with time zone
name text
value text
pk is timestamp

data tables are derived from this base table with constraint on year
month table_id
days table_id
1-7 1
8-14 2
15-21 3
>= 22 4
data tables are created pre-created before start of month
data_table_<year>_<mm>_<table_id>

No updates or delete will ever occur on data table except during purge
we will dump full table and drop it, inserting ~30 million per day
(every couple second data is loaded using copy statement).

What are the recommendation for vacuum / auto vacuum and statistics
generation ? Does vacuum on postgres catalog tables is enough to
overcome oid rollover or any other measures I have to take ?

Thanks,
YS