With that said lets try to get some more information.

Do you currently have a lot of shade in your new lawn?

Do your neighbors have St. Augustine? If they do what type? And is it doing well?

Is money an option/time?

If you have shade I would consider Bitterblue and option, but Palmetto can also handle shade well. Like I mentioned thought it will take much more time, money, and effort during the really humid months in Florida.

If you notice a neighbor with a really nice lawn I would question them on what they have and what they are doing. If that is an option.

No matter what you select I would follow these steps before sodding or seeding.

1) Round-up any existing grass/weeds in the lawn.

2) Till the lawn to create a good base to sod onto.

3) Get a soil sample and send it to a reliable soil testing lab. I would go with a UF extension office but I am partial .

4) Make any suggested corrections to your lawn.

5a) Once the pre-planting steps are done. I would set up a good plan on fighting bugs, fungus, watering, and fertilizer.

5b) Read into any problems with the grass/cultivar you select. What are the big bugs for that grass, and when do they attack so you can hit them when they are young. Check when fungus might be high so you can again apply before it becomes a problem. Water early in the morning (around 3-4 am) to avoid fungus problems. Fertilize with low amounts of nitrogen to avoid an increase in insects, and fungus.

6) Once you know this go ahead and enjoy your lawn. If you research and plan ahead you should see your time, money, and effort cut significantly and be able to enjoy your lawn much more.

So with all of that I will list my choices in order of best quality for least amount of trouble. Seville, Floratam, Palmetto, and Bitterblue(this is my last selection only because I do not feel this is the highest quality of cultivar for St. Augustine).

Hope all that helps