For jams and relishes I just use the method of the hot liquid going into hot sterile jars. I just make sure the pop top lid is still looking good. Have not had an issue with them sealing. Never tried turning them over, I just occasionally push down on the pop part (not sure if that helps).
I read you can get three uses from the pop top lids, you can buy more online if required.

I do have a Fowlers Vacola set-up, but I only use it for pasatta and other preserves that do need the full on hot water bath technique.