is it a 130 BCD and a74 Bcd granny ?, IDK.
well "Vuelta" being the Spanish TdF, last of the 3 grand Tours. in the year. its a name..
The Rotor brand is at least a Spanish company ..
http://www.rotorbike.com/company/history
but the OP is wanting low cost, not Pro cost.
what you need to set up is the chainline , so the planes []lets say the tooth tips,
of the chainrings and the rear cluster line up..
Maybe Bikes Direct service department will know all this, after all Its their Bike.