Standardizing the process of creating a new CurvesGeometry with
different curve sizes based on an existing curves is helpful, since
there are a few methods to simplify the process that aren't obvious
at first, like filling the offsets with sizes directly and accumulating
them to become sizes.
Also, in the trim curves node, avoid creating the curve types attribute
all the time. Use the special API functions for the types which do
some optimizations automatically. Also use a more consistent
method to copy the curve domain data, and correct some comments.