What is a reasonable air-conditioning schedule to prevent humidity issues?
This question has received a lot of answers and comments, but I suspect not from people familiar with Florida who have encountered the underlying issue.  It is a frequent one in Florida because:


There are a lot of snowbirds, and Floridians who travel a lot, so houses frequently are unoccupied for long periods.
Florida is extremely hot and humid.


The biggest issue is mold, which thrives in high humidity.  The problem here isn't humidity near 100%; the issue isn't the dew point or condensation.  Mold becomes a problem way before that.  The EPA recommends keeping humidity below 60% (ideally, below 50%), to prevent mold growth.  

The OP is in the Jacksonville area, where the yearly average outside air humidity is at or above this threshold throughout the day (low point of 58%, day average of 76%, high point of 89%).  House insulation acts like a thermal delay, so when a house is unoccupied for an extended period, it goes through cycles when it is cooler inside and the RH spikes.  In an unoccupied house with normal air infiltration, the inside humidity will be extremely mold-friendly.

Since RH is a function of temperature and the humidity of the outside air, it is imprecise and expensive to try to handle this by arbitrarily cycling the AC based on temperature or time.  To reliably control mold, you might need to run the AC more than required.  Also, you need a reliable way of knowing what humidity level results from your normal AC temperature setting.  If it normally keeps the house close to 60% RH and you arbitrarily bump the temperature higher while you're gone, it could result in a mold-friendly environment.

The standard solution is to install a humidistat (not very expensive and a one-time cost), which cycles on the AC only as needed to keep the humidity in a range where mold doesn't grow.

Note that, as d.george writes, this is likely to be much more regular than an occasional burst of AC.  It will be removing moisture from the air, but everything in the house will be storing moisture and contributing to the equilibrium.  How much it runs based on humidity compared to how much it normally runs will depend on the humidity level resulting from your normal AC setting, and the outside temperature and humidity while you're gone.  If your normal AC setting keeps the humidity in the 50% to 60% range, the system will run about the same amount via the humidistat.  If the normal AC setting keeps the house at a low humidity, it will run a lot less via the humidistat.

Another, or auxiliary, solution is to use a dehumidifier (probably several for a whole house), as d.george suggests.  You will need a way to get rid of the collected water so it can run for an extended period unattended.  These cycle based entirely on humidity.