Great, thank you for the information, really helpfull!
They both don't have a red belly unfortunately, but maybe they're still to young to show those, is that possible?
I made a movie of 5 minutes long, hopefully you can try to seks them. But if I do see your pictures and see my Ramirezi fish I de believe that I have 2 males (just cause of the body texture).
I did see today that on the bottom right corner of my tank, there's being played with sand. I can't say if that's from the Ramirezi or from the pleco's in the tank. I've made a photo of it.