I need 12v

i posted last winter looking for ideas to power a Holley sniper. Never got a clear answer, probably didn’t phrase it well. 70 Duster, stock wiring other than Crackbacks headlight relay and alt-batt connection. I have gone through and cleaned/replaced connections so pretty confident they are in good shape. I do have a wiring schematic.
I need 12v while both cranking and in run. It’s less than 3amps. What I did was run wires from ign 1 and 2 at the steering column connection, connect them and run them to the sniper. Although it works I read on another forum I am putting to many volts to the coil, it could overheat, also possibly damage my ignition box.
So how can I wire this to get 12v while both cranking and in run without causing problems elsewhere?