I wouldn't worry about the volts to operate the relays. It takes less than 0.1 amp to close the contacts in a typical relay, Bosch or equivalent, even though they can switch a 20-30 amp circuit. You have 14 volts going through a 2 ohm resistor with a 0.1 amp draw. 0.1 amps X 2 ohms is 0.2 volts. you have 14 volts less 0.2 volts 13.8 volts. It will work, use the same wire for both. Use the same wire to run a few relays.
I do not have a relay distribution business, and this is just my opinion. But it works for me.