Modify the pgsnapshot load script to more sensible defaults.

If you've got a large enough file to use --wpd you really should be using osmosis to build linestrings and bboxes if you require them.
Use ALTER TABLE ... CLUSTER ON statements to set what index to CLUSTER on.

This way it gets set even if the DB is not immediately CLUSTERed and the entire database can be re-CLUSTERed with just CLUSTER;

Note: CLUSTERing nodes on a full-planet database probably isn't practical.
Disable synchronous_commit for pgsnapshot loading