Procedural Spline Creation with animated shape extrusion. Help!

hi everybody,

this is my first post in the forum and actually my first attempt to write a script with maxscript.
My goal is to create splines based on the travelled direction of some particles (PFlow) and then attach
a primitive object (like a box or a cylinder) to the spline's first point and extrude it's top face
along the spline. This whole extrusion shall be animated, also the growing process of the spline.

At the moment I have no idea how to animate the spline's growth, so that each time a knot is created,
also a keyframe is added to it.
In the script I have attached to this post, I created a workaround where I create a cylinder for each
spline and constraine it with a WSM Path Deform modifier to the spline, also adding keyframes for the
percent along path parameter. Of course I want to replace this workaround with a decent solution of
extruding the geometry along the path with the correct amount of segments for each spline knot.

Help would be very appreciated, I already searched the WWW for solutions, this is how far I came.

all the best,

Manuel