Tomatoes only set fruit during favorable nighttime low temperatures. The difference between indeterminate and determinate is mainly that determinates set their fruit all about the same time while indeterminates scatter theirs throughout the growing season. This is great for areas that have cool nighttime LOW temps of about 60F-72F. The closer it gets to 76F the less the probability of setting fruit at all with 72F the optimum highest temperature. Also, high humidity greatly affects the pollen of tomato blooms. High humidity means less fruit set. What I am trying to say, I suppose, is that in an area such as Miami with its warm temps and high humidity that open-pollinated heirlooms are not a better choice than hybrids. Hybrids will give you much more production. Having said all of this, I still love to get a few heirlooms each year and for the, IMO, best tasting and highest producing medium tomato, it is hard to beat Arkansas Traveler.
I presume you want indeterminates if you wish to have tomatoes through xmass. If you planted seeds June 1 you could set out July 1 the hottest part of the year. I would plant seeds the first part of July and set them out mid to late August. But you must remember is that no tomatoes except cherrys will set fruit when the nighttime LOW temps are above about 74F. I don't know what your temps are during the fall and winter but the following varieties are what I would try. Porter, Mortage Lifter, Cherokee Purple, Arkansas Traveler, Large Red Cherry, Costoluto Gennovese, Opalka, Super Sioux. These are all indeterminate heirlooms.
Because they are indeterminates. You will find very few indeterminate hybrids in BBS. Hybrids are more disease resistant, that's why they are hybrids and by far the biggest percentage of them are determinates. The disease resistance is part of the hybridization. Growers these days produce a simple easy to use product. Plants that don't get sick although they do as you found out. Stick a hybrid into the ground, feed it and water it and the plant makes its fruit in x number of days. The less number of days the better. Whereas indeterminates produce until first frost, not just in 63 days or whatever the number of days the determinate is rated. Indeterminates produce longer and if taken care of properly will produce more than a determinate. A determinate produces all of its fruit in a relatively short period of time. But the deciding factor in your case is the hot weather in summer and no frost in the fall and early winter. If you planted determinates they would bloom, not set fruit and possibly, if you could keep them alive long enough, rebloom and set fruit if the temps were right.
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