To be honest, I don't think there's any such thing as a "Locator Jig". One must "locate" the fish, first, then offer them various shapes, sizes, and colors to find out what they're wanting at that particular time. That may change in an hour, so you're back to experimenting.

As far as fishing a large lake that one is not overly familiar with, I'd suggest sectioning off portions of it and concentrate your efforts to that chosen section. Picking a section that looks like a section of a more familiar lake is a good way to start.