I would not accept any leakage, but that's me. I found that my Vertical speed indicator glass was leaking so I put a thin coat of epoxy around the edges of the glass and so far all is good.
Then I found that air was passing from the static side to the pitot side of the air speed indicator, {not fixable and it was new} so I purchased a new one.
Then I found some plastic fittings leaking...Ahhhhhhh
Yes very time consuming to get it right...
Be patient you will get it right..