By the way, I was curious about other people who used an o-ring as a substitute for the Faemina Baby seal and I found a 2016 post from the HB website:Lever Espresso Machine Gallery
The main difference compared to my solution is that this one appears to take the original seal off and put the o-ring in the piston groove. But, the o-ring did not fit the groove and the person used a lathe to modify the groove, as I understand it. I would not like to modify the metal on the piston. If you could find an o-ring that could fit directly into the metal groove as is, it would be an alternative to putting the o-ring on top of the old seal, as I have done. Since I'm getting pretty good pressure and I'm able to make espresso, I think I'll leave well enough alone, unless I can get a new seal like the original.
I heard about ordering a custom-made seal like the original and a group buy a few years ago. Is anyone interested in doing this again or does anyone know a company that can duplicate the original seal?