This is great! I do the same. The photo was taken in June. When they get to the top of the post, they just bow over and keep growing.Now a few of my tomato plants are growing up and over the top of the trellis - about 7 feet - so I will just let them do whatever they want for the rest of the season.
I am sometimes pulling green tomatoes just before frost. That won't happen this year. We had a lot of rain, then Debby brought lots more. We pulled the plants last week. Thankfully I have a lot canned but no more fresh from the garden. I'll be planting the fall garden soon.