Update. I bought the juicer attachment to the big FP, which apparently does a great job of separating skins and seeds. Waiting for it to arrive.
In the meantime, what’s interesting (to me, probably not anyone else 
) - well a few things.
The cherries have A LOT more seeds and water than the other tomatoes (I have mostly cherry tomatoes growing). There was no bitterness when I cooked with the fresh tomatoes on a few occasions. So the vitamix was a bad idea, clearly, because it must have crushed the seeds. The FP did fine breaking them down without bitterness, as did the immersion blender.
So now I’m wondering whether to just run some of the tomatoes through the FP (without juicer) and leave them chunky, vs the passata that the juicer will result in. But there’s a part of me that’s a bit worried that cooking down the chunky sauce may still extract bitterness. An experiment may be warranted.
