No matter how you cut a s/s/s Strat Pickguard, you are going to have the left overs of the holes from the old single coil Strat PUP because the Single coil is so much wider than a standard Hbucker. Your two best choices would be to get an Hbucker in the standard Strat size of which there are many to choose from or Get an s/s/h pickguard.