Maybe I'm not understanding either, but what is wrong with the standard railing objects.
From image below,
1 - in object tool I searched used the Find Library Parts option...
2 - searched for "rail" and got lots of options.
3 - picked one from the standard library that has lots of variables
4 - you can set sizes, gaps, end cuts etc
Place one on your plan and stretch length to suit, and there is a curved variant too.
u can even see the horizontal ones in s2art's screen shot... most of the vertical ones even have a horizontal option with them... just look in the objects parameters. theres dozens of options and variants for each rail