sco, the common things that cause blossom drop are too much nitrogen, temps that are too low or too high at night, and things like thrips and genetics.
Could also be more than one of those things at one time too.

You're zone 9 so I would bet on too cold at night right now.

This is why I grow a lot of different varities and plant them out at different times during the season. Some will produce while others take a break, then they'll swap around.
My cherry, currant types, and plums seem to be unstopable though.

I had that problem earlier in the season-lots of blossoms and nothing setting--my best guess is either the temps weren't right or the plant wasn't mature enough to fruit just to blossom.

Heirlooms grow differently than hybrids, some of them look downright puny, but that is their genetic background (a lot of the plum heirloom plants look puny).
Now ALL my heirlooms have set fruit with nothing done except to add one flower next to Big Zac which refused to set fruit (that one is not really an heirloom). Now it has 3 fruits, but you have that covered.
What are the names of your heirlooms? My best results came growing eastern Europeans in FL winter. Have you tried Stupice?

It's a constant learning process...

scoville

The expert gardeners before me have answered you with the possible reasons for your tomatoes not setting fruit.
I am in Orlando and it is chilly at night. Maybe you set-up the plants too late in the season?
I follow the calendar since I am new to Florida but not to gardening tomatoes either heirloom or hybrids. I do prefer heirlooms.
I do have my favorites that also changes according to the season, weather, soil where I am living, etc., etc.

Denise

Overall which one(s) are the most successful tomatoes for you?. Taste and production wise?
How are your Goose Creek doing?. I have mine on my porch since I am planning to save seeds, which by the way it sounds to be a problem, been the seeds so tiny. I am afraid when I clean them they are going down the drain.
Any advice saving seeds this small?
If you have a chance I would like to see some pics of your garden. I like to learn from other gardeners, there is always something new. Like you said it's a constant learning process...

Willy

scoville, are they getting full sun and lotsa water?

"Any advice saving seeds this small?"

Willy, I found a little white plastic strainer at the hardware store. It has very fine mesh, like woven nylon fishing line.

If I'm only saving a few seeds, and know I'm planting them next year, I don't go to a lot of trouble with them.

I just put them in the strainer under running water and clean them by squishing them with my finger.

Lay them out on a paper towel to dry.

Then put them, paper towel and all, in a labeled paper mail envelope in the pantry.

Next year, they will be still stuck to the paper towel and that makes them easier to handle and plant. I just tear them off, and plant them with the little piece of paper towel they are attached to.

Willy asked

Overall which one(s) are the most successful tomatoes for you?. Taste and production wise?

Stupice and Black Cherry are reliable and successful for me, very productive. This year (new to me) Mariana's Peace is VERY productive but curiously one plant (productive one)has regular foliage and another one has potato-leaved foliage. That could be because it was free seed from GW :-) My favorite tasting one is Black Pear but it takes a long time to ripen and I haven't grown it yet this season.

How are your Goose Creek doing?. I have mine on my porch since I am planning to save seeds, which by the way it sounds to be a problem, been the seeds so tiny. I am afraid when I clean them they are going down the drain.
Any advice saving seeds this small?

Sadly none of my Goose Creek seedlings survived. This is the second year I've tried to grow it and must take it as a sign to give up. People rave about it, oh well...
Corrie's suggestion about a strainer is what I do but I dry on a paper plate and then scrape them off when dry. Got this idea from the Tomato Forum.

If you have a chance I would like to see some pics of your garden. I like to learn from other gardeners, there is always something new. Like you said it's a constant learning process...

Pictures? My garden is not impressive like others here :-)
Plants are tucked in wherever there's good sun. I've got some green tomato photos in the camera (hybrid "Polina") with about 20 tomatoes on a 3 foot plant. I may be on crutches in a week or so and will have time to upload photos to the forum (nothing else to do).

Denise

Corrie

Thank you very much for the great advice about the seeds. Exactly what I needed!
I am going to look for the strainer too, I hope to find it at Ace that is closer to me.

I love your tip on the Pantene Prov and the whitefly. I am sure to use it when I will needed it.

There is no book that can answer you when you have a specific question, that is the reason that I love this forum, the feedback is so great. Thanks Corrie.

Willy