Backup. Backup. And then backup again. Then
CONVERT your MySQL table. Don't just change the collation, actually convert it. Then
REPAIR your tables (also through SQL) so your tables are optimized as they are rebuilt (this is also what what the sql REPAIR command does). Next rebuild your tables in Control Panel > Content Rebuilder. Probably overkill, but i did it without loosing any sleep worrying about not doing it.
If you are for certain that you have not introduced any extended character sets to your database, you most likely will not have any problems.
I have roughly 4,000 users browsing that forum every day since about 2003. When there is a problem, I hear about it
I haven't heard anything relating to character sets displaying funny or post not able to be edited because of these changes.
