Have you checked over on the Lawn Care forum? Some of those folks are very knowledgable about our St. Augustine and Centipede grasses.

Here is a link that might be useful: Lawn Care

The Clemson Extension has a few pages on lawn maintenance.

Here is a link that might be useful: Clemson Gardening

The UGA Extension Service has a very good publication that covers lawn grasses that are commonly grown in GA. You can download it at the link below.
Rb

Here is a link that might be useful: Lawns in Georgia

UFL reccomends 2.5 - 4 inches for St Augustine - no seasonal change. Should be about the same for you in Alababm as here in NE Florida. See link below.

Here is a link that might be useful: Mowing Your Florida Lawn