Tomato plants - allow flowering or pinch off?

I am in Vancouver, Canada. Zone 7 / 8.

Thanks to a late start on my part in combination with terrible weather for the first half of the year, my tomatoes (from last year's seeds) got off to a very slow start. I have two beefsteak plants and 9 what I'll call mini-Marzanos; the grand-parent was a huge Marzano, but the next generations are in the 2 inch range. Thy are an indeterminate varietal.

The first fruits did not appear until the first week of August. With the extremely hot weather since late July and August, the plants have gone crazy and there's a reasonable amount of fruit, though nothing like the last few years. There are also A LOT of new flower clusters appearing

Based on the last few years, the latest I can harvest is about the mid to late September, after that the rains will split the fruits and rot the plants.

At some point we know new fruits simply won't make it long enough to mature and ripen, so my question is, does it make sense to pinch off the new flowers and will that encourage more energy to the existing fruits and get a better return? If so, when?

I attach a sample of the present state of the fruit and what it looked like last year before harvest (now +30 days). Last year's harvest was in the 1000's, I expect this year's be be in the 100's, from the same number of plants.