Feather models? Any differences?

A new barber opened shop in the town right near me. And he is doing straight shaves!

But he is using a true junk shavette style razor, that I can tell he is not happy with, and I know that my face is not happy with it either!

I am working on getting him into real straights, but for the business, he has no choice but to go disposable. So I was thinking about getting him a good razor to work with. (the more shaves he does, the better he will get, the better MY shaves will be!)
So, my question is, Is there any actual difference other than price and scale material between the various types of Feather brand Club razors? I see the SS , the DS, the RG (am I missing any?)
If there IS, is it enough to warrant one over the other?
They do all use the same blades, right?

All info is appreciated!
Thanks guys

There are small diffs on the holding parts of the various models, but from what I have seen they are not all that noticeable when actually shaving.
A slight hollowing seems to be the major diff really.

And yes, they do take the same blades as far as I know.
When I bought mine there were 4 different blades offered.
The guarded version called pro-guard(?), the light, the professional and the Super professional.
They are all equally sharp, the difference being blade protrusion.
The Super Professional is noticeably further out from the jaws of the holding mechanism than the light version.

There is a slight difference in the face feel of the SS vs the RG. I thought that the RG had a little less blade exposure, and I liked it less.

Incidentally, there's a cheaper knock-off of the RG that works about as well.