RE: The Rolls Razor
I have one in good condition. Mine has the outer box and instructions booklet, dated 1951. I got an average shave out of it after having the blade professionally sharpened by Neil Miller. I've read that the strop and hone don't really sharpen the blade wedge much, but they probably weren't using a mint set like yours. Also, having used DE blades from around the same time, it was probably pretty good by those standards. It gave a comfortable but not exceptionally close shave for me and I'm spoiled by some of the DEs and injectors I have, so I can't say it was bad.
Lay the wedge almost flat on your face to get the best shaving angle.
I don't know how soon you would need it but if the leather is quite dry you might want to get some strop paste.
Let us know how you get on with it.