I quite often use the Trussmaker accessory to do these kind of railings. If you use different pen colours for the handrail, balusters and posts you can control the dimensions and shape of each type of element.
For curved in plan railings use the
Profiler accessory / add-on
If the railing is curved in plan and going up a slope as well then you do need to resort to a full blown GDL object. If you have a copy of the GDL Cookbook there is a Spiral Railing object
All the best
AC versions 3.41 to 25 (UKI Full 5005).
Using AC25 5005 UKI FULL
Mac OSX 10.15.7 (19G2021) Mac Pro-2013 32gbRam AMD FirePro D500 3072 MB graphics