This is a photo of my greenhouse tomatoes in my Alaska Grow Buckets just three weeks after transplanting and looking very healthy. I use commercial hanging string trellis reels with tomato clips to support my plants. These tomatoes were started indoors in February and are now blooming in June with a few tiny green tomatoes. So these plants are mature and starting to set fruit. They will continue to grow twice this height, or more. Harvesting ripe tomatoes begins in August and continues until cold weather returns in September.
I use this string trellis system with tomato clips in my greenhouse and they work great.