Estimating overview size

[Chris Martin]

In our development system 48% of a partition of 1164532 1k-blocks
contains overview data for 1387329 articles.

The spool size is 3774828 blocks (cycbuffs) plus 55276 (tradspool) --
a total of 3830104 1k-blocks.

Assuming that the ratio between spool size and overview space used
holds, this means that the ratio of overview space used to spool size
is 1:7 -- to allow space for expireover to work, allow 50% more
overview space giving a ratio of 2:9.

With a planned spool size (for our new server) of 33 Gb this would
require just over 7 Gb for overview data.

Would any of you very experienced news admins care to comment on this
estimate -- or the way it has been reached?