My only suggestion is to have a soil test done through your local Co-Operative Extension Office. They have saved me from frustration on several occasions as you can not tell the quality of a product when looking at it. If you are buying in bulk a company should not have a problem with you getting a soil test prior to delivery.

I use Fafard (name may have changed, but nursery will know it). It's expensive, but the increase in my garden yields have been tremendous. (from bags bought at big box store)

Since you haven't gotten a lot of replies, a popular way to do this is to put down sheets of cardboard (see if you can get boxes from appliance stores) followed by compost, something like mushroom compost if you can get it in your area, then a heavy layer of mulch, something like pine straw or pine bark.

Yes, David the Good is a great resource, but for FL-specific stuff you need to scroll back a ways since he's been in Central America for some time now, in quite a different kind of topography/climate.

I know he recently moved to Central America I still follow him.

And easy way to test your soil in any part of the world is the simple Jar test.