I think it might be better to recode the airport scenery autogen to automatically add a ‘GA Dock’ parking object to ANY airport where there is no parking apron recognised by the AI.
This means both water runways and bush strips will get a parking spot. And you want it to be GA Dock as this is the only parking spot type that will not spawn inappropriate ground workers.
This would give both bush plane and seaplane enthusiasts the c&d and shutdown spots they want!