Hello Charlie, I make a lot of jams but I never use those jars for that purpose. I do use them for storing dried porcini, herbs etc.
You mention 2 very different preparations; jams and preserves. Preserves like vegetables, stocks, etc. have to undergo a sterilization process when using your jars. The most traditional method is to submerge the pots in water in a very large metal recipient, protected with cloths, and boil them, let them cool, so they are closed hermetically. When opening the pots you need to pull on one of the lips on the rubber rings. Maybe one of the forummembers has a more modern technique?
On the other hand, there is jam making. In the past, people used thick glass recipients that had no lid at all. You made the jam, poured it in the glasses, leave to cool and then poured some melted wax on the surface. Then they covered the glasses with a piece of paper.
You can use your nice jars, but you need to fill them very high, up to the smallest part, so you can easily remove the wax.
However, I would suggest to consider using simple jars like in the picture for jams. The lids are clad with a thin layer of some kind of rubbery substance that will close the jars hermetically... when used properly. Before filling I always put my jars in a medium hot oven (temperature just above boiling point), NOT the lids. Then I pour in the hot jam when coming straight from the fire, close them and immediately turn them upside down for at least 30 minutes. That will seal them thouroughly. Turn them upward and job done! I recently opened a jar that was 3 years old and it was still perfect! As you can see, I recycle jars too. Storebought jars from jams, olives, mustard etc. are perfect.
Here's a batch of strawberry jam I made in june;