This is just a coefficient for the whole spline. Once you set it to a value, you can then scale any spline point and it will use that factor as a base:
If you’re doing it from blueprints, in the CS - ensure you tick Input Spline Points to Construction Script. Assuming the forward is X, you’ll want to scale Y if it’s a road.
Unless it’s a road to crazy town, who knows.
I am worried about Consumeing a lot of performance use splinemehs
Once left to their own devices, they perform well enough. Updating them in real time (tick) is a performance hog, though.