Keeping strawberries sweet
Ideally strawberries should be picked the day they're eaten.  Adjusting your shopping plans to the day before or so would be best in any case.  I've never heard of this vinegar bath trick, but I've sometimes kept strawberries overnight that I had mixed with lemon juice.  They're not less sweet, but the texture is blah, going on mushy.  I would experiment at least a day or two with your vinegar bath before relying on this for an actual holiday.