Sealing stringer drain holes
 

I have the back seat out of my 272, so doing some maintenance. Was thinking of sealing the stringer drain holes (right where the stringer meets the transom).

The boat is dry and stringers are solid; just being pre-emptive.

Best way to do this? Was thinking of sanding the hole, and coating with polyester resin. Just want to ensure everything is sealed.

Thanks!