Quoted from blownfuse:Here's the difference in the spot targets for those that are curious. Sorry I don't have any pics of the Spirit's I worked on last year but here's a comparison from a Bounty Hunter I'm in the middle of. I also mylar my targets so they don't wear off if they have print. I use a punch for the rivet cut out and use nail clippers to trim off the excess mylar. Hopefully this will help someone.
Steve
Great tips!
Also worth noting - those System 3 spot targets also work great on WMS System 3-7 games. You do need to remove one of the skinny bakelite spacers and add a diode lug, but besides that the switch and bracket dimensions are identical to sys 3-7.