That looks like new!
I mearsured from the roof of the lid down 23mm and made my line on the small jar. Then when my fuel leveled out at that line I considered that right. Put it all back together and it runs better than ever. My clear pre fuel filter filter stays completely full now as before it was always filling itself at idle that I could watch in my garage.
There's another popular way but I haven't tried it. I think it would be easy for you now that you have yours apart somewhat. Google "fuel level 10 turns down classiczcars.com".
Here's the jar I used, figuratively. Close anyway.
You might take the opportunity now to, fuel resistant RTV, "glue" the cork gaskets to the lids.
I'm using my phone now but can try and clarify this post better Saturday. Waiting to be seated, patiently...