Quoted from Timm:Another method of lining up artwork is too wet the surface with soapy water so that the Vinyl floats on top of the play field then squeegee the liquid off once it is aligned.
https://www.edcheung.com/album/album07/Pinball/apply.htm
This is also a good idea I’ve had great success with arcade decals using the wet method. You don’t necessarily need to use soap. I use glass cleaner. There is a fine line between too wet and too dry because you can cause a lot of air bubbles. Buy yourself a squeegee at the dollar store to smooth out any issues.