Got it now!
I've only done the first approach with colorize options and for the purpose of making a grey armor it worked just fine, as it only slightly darkened the blacks which I planned to keep black anyway. I'll also play with the map and rotate color section to see what I can get that way.
I don't think I'm colorblind, although it may be questionable after thinking that the comics' red was of a different shade, lol.
Once again, thanks a lot for your help. It is much appreciated!
Edit: Yup, I get it now. I made the orange one for fun. (I am yet to figure out how to make a grey this way, but I'm getting the grasp of this). Thank you very much!