I have 2 peaches and one nectarine, like you, in Pinellas. I have always had best luck pruning my trees so that they grow up, i.e., taking off all the downward growing branches. I had a bumper crop this year-should have pinched off half the blooms-I would have had less fruit in numbers but bigger individual fruits.

Thanks for the information. Do you prune to keep the branches shorter also or just take off the downward branches? Do you take the leader off the tree?

you read this, right?
http://edis.ifas.ufl.edu/HS365

it may be too late to keep your older tree small, but you might consider making a radical cut this winter on the smaller trees. on my one-year old tree, i cut the trunk down to three feet. this year, i've summer pruned it into the vase shape recommended here in fla.

summer pruning is key if you want smaller trees. google "dave wilson dooryard orchard" for his detailed explanation.

the gist of that ifas pub -- peaches and nectarines bloom on one-year old wood. so, to maximize production, when you prune during the winter, remove older wood when possible. and prune so that there is a lot of "new growth" (previous season) that is strong and capable of holding fruit, and maximize the branches in that category that are around the perimeter of the canopy and within easy reach.