No worries with a short no wake zone like that. When I say extended idling I mean more like 15+ minutes at a time. So long as the cam is already broken in you're fine. Letting it idle for a few minutes at the dock or through a no wake after dropping it in is good to get some temperature in the block and oil before putting a load on it when getting on plane. The first 20 hours or so on an engine are not nearly as critical as the first 20 minutes of cam break in.