That doesn't sound right.
Are these the instructions you have?
View attachment 1715785518
The only "hot" wires are switched feeds from your ignition switch: "Ignition 1" (run) and "Ignition 2" (start). Basically the same wires that were there for your points ignition. Do NOT use a constant hot.
Yes, the voltage through the ballast will drop; that is the purpose of the ballast. The system provides full voltage for starting and reduced voltage for running- full time constant 12v will cook your ECU (unless you run an ECU specifically designed for constant 12v).
