OMG your submission is amazing.
So you are right I assign each colour a number and memorise the cube face by face.. then I visualise the cube in my head and solve it in my mind whilst simultaneously solving it physically. If you want to get into solving blindfolded then the way I started was I would scramble it and memorise just one face and then cover the cube and redraw the face on paper and then check. When I got better I gradually increased the number of faces I memorised until I could do the whole thing!!!
Hope this helped ;-)