The least point elastic is a Bonnell spring core. Are the individual springs sewn into rows of cloth bags and these rows clamped or glued to a surface in mattress size, it is a pocket spring core, which has a good point elasticity, but is only partially suitable for adjustable slatted frames.
The highest comfort is provided by the barrel shape pocket spring mattress, in which the metal springs have a belly shape and thus are considerably more flexible than pocket spring mattresses.
If you desire a compromise between pocket spring core and better bending load capacity, then mattresses come into question, which alternately offer rows of pocket spring cores and foam from head to foot, thus combining the advantages and disadvantages of the individual types of mattress.
Machines for the production of pocket springs can be found here: