Iron Pete, I have never missed a year without Stupice since I got my original seeds from my first TGS seed catalog. I don't even know how long it's been - 15+ ??? years. I keep trying other earlies, but my saved Stupice seeds always beat out everything else. Vladimir shared some recently produced Czech Stupice/Stupicke seeds with me and the Stupicke Moravo was ripe the same day as my U.S. one. The Stick tomatoes are kind of a cheat because they were started in February as part of a germination test. The Bétalux started blushing about the same time as Stupice, but took longer to get to eating stage.
I started my seeds the last week of March, and they went into the garden the last week of May. Picked off the vine on July 2nd, but I could have taken them in the last few days of June. I don't think I've have an in-ground tomato ripe before the 2nd week of July before.