Hello,
If you're uploading the database through DA, the filesize limit is setup in the Admin Panel -> Admin Settings (bytes). Default is 10 meg.
If you're using phpMyAdmin, then that's a different story... It would probably be limited by php, in which case you are probably on the right track.
No, you shouldn't need LimitRequestBody .. it's default is 0, which means unlimited so adding it would only contrain you more.
John