Don't worry about using different blocks, your phone controls the amount of amps it wants, it can't be "given too much", as for voltage, all usb chargers for phones will be atleast 5V, which all phones can charge with, some can also provide different voltages, but like the amps, this will be controlled by your phone.
Your phone changes the way it charges all the time, often within a single charge cycle, based on temperature, battery level, usage.
