Tomatoes are so fussy. I'm trying to make sure the calcium balance in the soil is good...but man, it's a battle. That's good advice for the seeds, though. Maybe when I finally master growing them, I'll start on the seeds.
Cal mag is readily available around town garden centers
Soil ph can lock out the nutrients too making them unavailable
You sir, are a specialist in the art of discovering a welcoming outcome of a particular situation....not a mechanic.