440 Build

Engine Balance Question

Going to wake up this thread to avoid clutter.
I have an externally balanced rotating assembly.
I need to know what I should bring to the machine shop for balancing.
Crank, pistons, rings, rods, rod bearings and harmonic dampener I have now.
Do I need to get a flex plate and torque convertor? Can these be acquired and balanced at a later date?
Should they be technically balanced from the factory already and just bolt them on?
So many questions. lol

thanks guys