I did use the wet method on my funhouse as it does make it really easy. I even did the bumper decals to get them perfect. You don't need to saturate them in liquid but I would still be worried about the autograph. My tip is wet down the decal and use say a tissue or clean cloth to push out the Windex. Just make sure when rubbing near the signature, the cloth etc is completely dry and just slowly swipe over the top, each time ensuring the cloth is dry. Should work I think