You do know that on the Firepower site there is artwork for the cab stencils? I have no idea how you get them printed into something useable, but someone on the forum must know. There's a few of us with machines that could help with measurements to locate etc if that's any use.
If it's the Jeff from Classic Arcades good luck on trying to communicate with him. Doesn't seem interested in answering emails - his loss as I was wanting to buy a single decal I needed, fair price and all. Would have bought the full set for the machine - drops, spinner etc if he'd combine shipping but since he didn't answer my email question and since I wasn't prepared to pay an extra ~US10 per item shipping he only sold the one I needed rather than the full set.