How to determine the half-string capacity of a multi-stage pump

Without using a bearing frame or balance disk, the impeller is secured in place with shaft sleeves; the length of the balance disk can be replaced by old shaft sleeves. The impeller is pushed towards the drive section, and a depth gauge is used to measure the distance of the impeller from the pump body; it is then pulled back again to determine the total offset. Half of the total string length corresponds to the alignment position of the impeller; then the balance disk is installed, with the gap between the balance disk and the balance ring being within 30 microns. Finally, the bearing frame is installed. I’m also figuring it out on my own; I’ve only been working with this for a short time. If there’s anything wrong, I hope some experts can give me some guidance.