Major upgrade advice

I'm getting ready to tackle another upgrade: 7.4.6 -> 8.3.3. The
preliminaries (development/testing) look good but I'd like
suggestions/warnings/comments on:

1. Removing OIDs on user tables.

I don't see any dump or restore options to remove OIDs. Am I better off
modifying the dump to alter the "SET default_with_oids = true;" lines or
going through all the user tables in advance and running "ALTER TABLE
... SET WITHOUT OIDS"? Other options?

2. Alter encoding from C to utf8.

Cheers,
Steve