That being said, I'm going to make a no-cost suggestion. If you are running your fan all the time, put the fan on automatic ( on only when the AC is working ) during the day. This allows the condenser coil to do its job (dehumidify) much more effectively. I did this in my own home and saw dramatic change in humidity-much lower and more comfortable. If you try this, please E-mail me and let me know if this works for you, too. Thanks!
I am still running the fan all the time from 7:00 PM to 7:00 AM to move the cold air to the upper ( bedroom ) level.