How to make the evenly distributed circular tubes on the surface become dense and sparse, and then distributed to the dense tube

How to make the evenly distributed circular tubes on the curved surface become dense and sparse, and then distributed from thin to dense circular tubes. The following is the project file I got, can help me improve it, thanks

桥梁扶手1.gh (18.9 KB) 桥模型_圆管_9_10_最后-1.3dm (8.8 MB)

You could try something with the graph mapper for the density of the pipes along the curve.point%20density points density.gh (8.9 KB)