the decal would be easy , once it's reduced you can print it on white inkjet decal paper.
If you still need it , I can reduce it tomorrow when I'm on my other computer, and post it here.
It would take a page to explain how I do it.
In a nut shell I would print it and measure the diameter , than come up with a scale factor.
go into the photo program and reduce the photo it by the scale factor.
than cut out the disc in illustrator or photoshop.