While there's no requirement for non S brand cranksets to have the same ring C-C dimensions (which are a big determinate for index shifting) the market place pretty much wants it. So i suspect that the vuelta is S compatible in this aspect. next concern is the ring sizes and their differences. S brand ders like both certain ring sizes and the amounts of teeth count differences from ring to ring. The shapes of the frt cage is designed around this. So the Vuelta having the same ring sizes is a good thing.

What does change though is the ring tooth profiling, shift gate shape and lift pin designs. Here's where S brand has it over most all other companies. S has done to most extensive research and design over many years to insure the best shifting (within the design specs). Other companies, that are common even as OEM parts, don't have as nice front shifting. But since rider technique is an even bigger factor a well schooled rider can shift second rate designs better then a klutzy rider shifting a Shimano crankset.

As to the 30T ring interchangeability, they are likely so. Both the S and the no name inner ring likely use the 74mm bolt pattern. But one measurement is worth a thousand opinions. The bolt to bolt dimension for a 74 mm circle is 43.5mm. Andy