What's his actual height supposed to be, about nine feet?
i don't know what it should be.
actual height can be approximated from these two images that show a human figure in direct contact with Cain, unlike other shots in the movie. there is also a scene with two dolls who seem to be in scale, judging by that human/cain torso photo.
i'll try doing it.
wait, there is a better option.
Cain is at his minimum, dormant height here, and he is like 356 pixels here, and the biggest Robo doll, standing on his left (on the right for us), is 282 pixels.
356/282=1.26.
16.5" Robocain means that Robocop should be 13.1".
if somebody can measure HT Robocop now, and he will be of that height or less, and if 16.5 for Robocain is his dormant minimal height, it will be a perfect fit.
though he must have had some Krang-like magnifyer
(people on the right side)