I was thinking about using either conduit like that or rebar. Glad to hear it worked out well. Pruning sounds like a good idea too, it's finding the time to prune that's the real hurdle.Last year was my first year trying hard pruning and WHAT A DIFFERENCE. It felt painful at first to be pinching off so much healthy growth (especially if I got behind and had good-sized branches to prune off,) but the plants were SO much healthier and productive. The increased airflow and zero contact between leaves and dirt really diminishes opportunities for problems.
I also trellised on just string like they do in greenhouses for the first time, even though mine were outside. I had EMT poles running along the tops of 6' tall t-posts and ran string between that and stakes in the ground, clipping the tomatoes to it as they grew. Loved it!