I had a very similar set up in my greenhouse, i also used to zig zag, 2 deep about 18" apart. It definitely makes it easier to snip of excess leaves, tie up trusses getting big, and of course harvesting. I also used to have a couple of cucs at the end of the row.
I do find different varieties of toms need different amount of space. I had a yellow tom that would always grow very tall and slender and took much less room than for instance the moneymaker, which is a big fat plant.