I considered doing the same thing to my COMIC-CON mask, making modifications and all. I am not sure if ALL of these have been mentioned in the previous replys, but I'll repeat them anyway. These are the obvious differenves between the Rubies, and Movie mask that I am planning to modify on my rubies;
-The slit in the mouth is way too short on the Rubies
-The eyebrows are rounded off on the movie mask at the front, but the rubies are straight.
-The mustache on the Rubies is more "squared" or "angled" where the movie used one is more "rounded."
-The beard comes off of the mask about .5 -inch on the movie one, but not the Rubies.
-The nostrils are more detailed on the movie used mask.
-As for the paint, the eyeliner, needs to be closer to the eye slits on the rubies, it is WAY to spread apart.
-The creases in the face, caused by Guy's Grin need to be deeper cuts in the Rubies mask, they are to shallow and undefined.
-The overall width of the Rubies seems to be too wide.
-The side string attatchements need to be hidden and concealed.
I'm sure there are more things I didn't catch, I know there are more obvious things with the paint job, but I'm not going to mention all of them. And I am sure that most of the things I mentioned above have been noted already on this thread...well...too bad.
Oh and by the way, whoever shared these pictures, thanks. I hope you don't mind that I am using them, it's for a good cause. And to the owner of the Rubies mask, I am not picking on you, I have a Rubies V mask myself.