He chose those values to aim for because 100 million volts for the potential difference and 30 thousand amperes for the current are the specifications for the power of lightning.
These values can increase by 10 times or more, so they are just the minimum values he has to achieve if he wants to be able to match the power of lightning.
His current power is 5,500 units. It is impressive for someone at the second mortal coil, but he is still too weak to create something that can match the power of heavenly lightning.
Even if he managed to achieve it, there was no way he was going to be able to control it. So he decided to be more realistic about what he wanted.
Instead of prioritizing how much voltage and current that the armament produced, he chose to prioritize making the armament work in sync with the lightning mark in his mind.
