Oh, I do worry about the pop top going down, they go down as the jars cool, I just have never turned them upside down to get it to work. Sometimes they will stay down if I press them, otherwise I will just hear a popping sound as they seal.

Forgot I have also used the cellophane seals an elastic bands with success on quince jelly.

For pasatta, I just put the tomatoes through the fruit/vegetables strainer attachment on the kitchen aid, then simmer on the stove for awhile to get rid of some of the water. (My first batch separated in the jar). I then bottle in Fowlers jars with some citric acid.