another scupper questions

[Mikem8560]

I have flappers now and plug I put in and tale out it seems it be nice to have something better I heard the ping pong type can be fouled with trash washing out the scupper and the cover has to be removed, how are the duckbill style id think any thing that washed out the scupper would clear out much easier not getting trapped. I was also thinking they would be good on the motor well drain rather then the plugs as I have fopr them also .

any feedback from experience with these ?