Since Foswiki 2.0 the FOswiki core uses unicode. This eliminates the need to convert between character sets, as unicode is a superset of all of them.
Support for UTF8 is good in all of Postgres, MySQL and SQLite, all that's required to use them is to test and tweak to ensure unicode names and data
are stored and restored correctly.
SLQ Server is a complete pain in the arse, and may require significantly more effort to get working.
-- CrawfordCurrie - 11 Apr 2017