I'm planning to just keep lowering them as they reach the top, the trellis leans very slightly forward to make it easier. The potting mix was had a little steer manure and compost mixed in for nitrogen, now that they're starting to flower, I'm adding some masterblend 4-18-38 once a week.
Only 5 plants! There's only so many tomatoes the two of us can eat! Mostly, it's because the grow bags came in packs of 5.
I think next year I'll get the 10 gallon grow bags so I wouldn't be surprised if I somehow managed to convince myself to grow 10 plants in 2019.