Interesting. Do you find the contrast between alphas and numrow/punctuation and the modifiers makes typing easier?
Really not too much. This keyset was made with this weird industrial aesthetic in mind, so it isn't 100% functional, first of all I don't need to see the keys to write so I can't help too much.
For readability there are other important factors. The font is one of the most important things that affects readability and this one isn't too readable, maybe a Helvetica could be better (during history every font has its function, try to find one that suits a keyboard). Bigger doesn't mind better, in the photo you can read the letters very well, but in reality the alphas are a bit too big, with little blank space around that isn't good. Also, the different colors make it fun, but I think that isn't helping as, for example, if someone tries to find a character it won't be easy reading it when there is a bright color next to it.
I think that this is an interesting topic, I don't know if someone has worked on this before (I imagine there should be).
Reached this point I think the best way is to print the set to its full size and make a study between people with visual impairment if that's your goal.