Ballast

It is not so much the voltage at the coil for cold starting but the current through the coil; spark energy from a coil is proportional to the square of the current, so more current is better when cold. So, a ballasted coil with the ballast bypassed for starting will give you more coil current and thus more starting spark energy.

(HEI is a very different situation so this discussion is only for a 'standard' ignition system, like the Mopar electronic or points.)

For the OP and his friend, the 'no ballast' is OK if the coil is a 3 ohm coil; it just won't have the cold start feature mentioned above. If a standard 1.5 ohm coil, then a correct ballast is needed. The MSD 0.8 ohm ballast is a pretty good choice; I'd prefer the the Mopar 2095501.

BTW, for racing, when the use is not continuous, it is common to use a very low ballast resistances to get the coil current up, especially at higher RPM's when dwell time is short. But these are not meant for street use, and will overheat the coil after some time, like 20-30 minutes. Some folks think that if it is good for racing, it must be good for everything...LOL