OP refers to a previous post. Might be
this one. However, I can't see any info in that thread about the bulkhead doors that are mentioned in this thread.
I'd suggest getting some single-sided sticky foam tape, such as is used on boat hatches, to obtain a more weather-tight fit. But not knowing the actual construction of the doors, nor whether the fix is to prevent leakage while closed or to prevent overflow when the door is first opened, I'm just making an uninformed suggestion.
Perhaps a better description or even a photo might elicit more responses.