Self Bailing - 20'

[JCB]

I am new to the site, and am an owner of a 20C. This is the first year it will be kept in the water. I have been reading, researching, and experimenting to find the best solution regarding the self bailing/below water line scupper. The past few days at the dock, water drains easily, but slowly off the deck. The through hull is an Attwood Stainless with a rubber flapper valve. I put an inline check valve in the 1 1/2" hose as well. Since the through hull is below the waterline (not advised from the manufacturer) water will remain in the deck drain lines until the boat is moving. I came across the Perko Bronze Cockpit Scupper which utilizes a rubber ball in its housing to to prevent backwash. Currently, at deck level, there is a plastic drain with no backwash preventer. Has anyone tried one of these perkos? Is there any other method to deal with the wet deck? I love the boat and the ride, but the scupper issue is pretty annoying. The boat is relatively new (2001) with a new 150 two stroke yamaha. Any tips or advice would be great! Thanks! jcb