Suckers, pruning and more of the like...
I think you make a good point - that the heat and longer growing season may make pruning the suckers less beneficial (or in your case detrimental).
With our shorter growing season and with none of the excessive heat concerns, we do find pruning is assists in producing larger (albeit a few less) tomatoes. This ensures that the plants energy is not expended on weaker (read sucker) limbs and their fruits, which won't grow large enough to ripen anyway. It also helps not to have to stake up all that unproductive foliage...
And speaking from experience, yes, suckers will produce fruit - but they're just little suckers ;o)
That said, only the indeterminate varieties, the ones that grow very tall (8 feet for my cherries!), are pruned. Pruning determinate or bush-type varieties actually results in fewer tomatoes.
Oooooooh I'm gettin' a cravin' for homegrown tomatoes!