I have used Kwik Patch. It's OK, but don't try to rush it too much. It takes several hours to set up. With that big a scratch, I'd put it on half the scratch, then come back the next day and put it on the other half. Then give that a day to cure before working it out. Another option, if you've already got plug materials, is to mix up a small quantity and let it set in the mix cup until it starts to set up. When it gets quite stiff, use a spatula to smear it into the crack, then let it set up completely. I've never done this myself, but it was demonstrated in the pro shop class I took. -- JohnP