i work as a development engineer and balancing involves my component (e-motor) as a part assembly of an electrical scroll climate compressor for cars.
So talking about balancing a component, a part system and the full rotating assembly. Actually balancing is complex but not difficult as long as you are not pumping fluid or gas through a scroll
A mechanical Engineer should have the skills to calculate through the system. An experienced mechanical engineer will do that pretty quick.
Just imaging every component as a balancing plane. Very easy with gears. Each and every component has a resulting vector pointing into one direction with a certain length. This is the grams of imbalance times the distance from the center. 1g * 10mm = 10gmm imbalance 10 mill from the center.
If the component are positioned from axially from each other you take this into consideration also as a radial gap.
Now what you do is to check the imbalance of the HPFP and put it into your equation. There might be of course the target that there is no imbalance in the HPFP which is completely unrealistic due to manufacturing tolerances. And i doubt that the HPFP is active balanced during and after assembly.
You have to counter balance the resulting imbalance from the HPFP (if existend). The Helix and the HPFP have both their own static and dynamic imbalances. They can eliminate each other or add up.
If their is only ONE position of interface of the Helix for attaching to the HPFP than chances are that they did counter balance the HPFP.
If you can rotate your helix as you want before attaching it randomly to your HPFP you start gambling! In EVERY case you are manipulating the resulting imbalance of the system.
A) Counter balancing - Good
B) Staying same with vector pointing into another direction - No Change of the system
C) You are adding imbalance - Very Very bad especially if the system now got longer
I hope you can follow a bit of my words.