Similar to the "infinity lights" setup on my Xenon
the Gallery of images has a good shot of behind the Space Invaders glass ... held in by small plastic wire looms like https://www.cabletiesunlimited.com/1-8-black-light-duty-cable-clamp-3-8-wide-100-bag-cc3-1-8-0c.html?gclid=EAIaIQobChMIntzzr-PD6gIViAiICR3qEgsaEAYYASABEgLmQPD_BwE
https://pinside.com/pinball/machine/space-invaders/gallery
Here's some pics I snapped if they help:
IMG_2070 (resized).JPGIMG_2071 (resized).JPGIMG_2072 (resized).JPGIMG_2073 (resized).JPGIMG_2074 (resized).JPGIMG_2075 (resized).JPG