inspired by hooked on pinballs spinner mod for met pro i did the same for my GOTG. The layouts of the machines are similar and the mounting spots are about the same, it does requires notching the orbit plastics , they are hooked to the # 2 hadron target so the first spin will spot you that hadron and you get the hadron sound when they are activated , not a big effect on scoring . the hooked on pinball thread has some good referenced on mounting etc. I mounted mine a little higher in the orbits to keep from obscuring the character insert
https://pinside.com/pinball/forum/topic/new-pinball-hkd-metallica-pro-with-add-on-spinners