Whats the deal with the KB 243's, good or not?

The higher ring is to minimize the dead space between the top of the ring and the deck of the piston, think unburned hydrocarbons- polution

The high silicon hyperutectic alloy does not transfer heat as well as the other alloys, therefore the rings run hotter and expand more
simple as that
which is why the bore prep and plateau finish works
you want a coarse hone to hold oil and a fine finish to minimize oil usage and hold hP
Pleateau hone with a torque plate then a super fine bottle brush just before final assembly and clean clean clean works for me (ductile moly rings)
more important the narrower the ring
I rotate the bottle brush the opposite way from the CK-10