The angled clamps will do everything the big Y clamp does and a lot more, depending on how you position them on the machine. I think if money is an issue, the small clamps should work fine too. I can imagine that on narrow blades, the shorter clamp length, might required a steeper (bad) stone angle to keep from grinding the clamp. On most modern folders I doubt it would be a problem.
When I bought my system I got the R2 with the two angled clamps. I also got the M7 table attachment, and the scissors attachment. I bought the M7 table over the M3, because when the side table extensions are removed, it can be adapted to make a nice small blade table. The scissor attachment, gives me the ability to sharpen scissors, but more importantly, it lets me sharpen chisels, and plane irons. All together it makes for a very versatile system.
However after messing around with the R2 clamp part of it for a while. I doubt I will be using it much. I have a lot of traditional knives with small narrow secondary blades. Getting those clamped up accurately, while still not grinding the clamps, is a pain at best. I also have some ten inch kitchen knives. To do a good job on them I would need to reposition the blade in the clamps at least once. Again a pain. In between those extremes the clamps should work ok, but so does the table. I learned on a table system. I found, I'm more comfortable with the table system. So I expect my M7 head will get most of the use, and the R2 head will collect a lot of dust.
O.B.
