Re: Hooooooray I found the air leak!
Yeah, I tried some Permatex that claimed to be gasoline compatible, and it ended up being a goopy mess. I don't doubt that there is a stuff that would work better, but I decided to roll the dice on some o-rings (since I was buying a bunch of other parts anyway), and it worked for me.
It's been a while since I put the one in the neck by the intake on the newer bike, and much longer for the older bike, but I don't recall any issue with overlap with those slots.
When I eventually have to take one of these carbs off for some reason, I'll make sure to inspect those o-rings for deterioration, and follow up.