I really hate that putty. It is some nasty stuff. When replacing a light that has the putty in the jbox, I remove it and do not replace. The wire plugs are good if you remember to put it on before wiring up the new light. If not, I've also used Marine Epoxy to plug the hole around the wire. Also, as mentioned above, use butyl tape on the connections. I've run into a few that weren't up to code and flooded.