Might be worth sharing some images to help us get an idea. I’ve never heard of numbering piles using the spline tool?
For any numbering systems if it follows some logic you can normal automate it fairly easily, however, it kinda needs to follow some sort of pattern. For example, I work in MEP and I mark my lights from bottom left to top right.
if that’s the case look at the following:
If the numbering system is not that clear then I’ll need more information to help.