Unless you are going to use a dead soft coordinator gasket d use any wire in the groove.

Yo have two choices.

1. Machine the decks own enough to eliminate the grooves. If you have the room to machine that much off that is the best choice.

2. If 1 isn't viable, you need to clean the grooves out until they are as spotless as you can get them. Take some J-B Weld and fill the grooves. Le it dry and the file it down flat and go. I've done it both ways and both work.