Correct you are sir! DLC is tougher than CrN however CrN can be reworked whereas DLC requires recoating from the base material. Either coating can be run with a standard seat and both create a very durable valve job.

For a BBC 2.250 +.100 long intake the difference is between steel and Ti is about 50g i.e. 144 vs 92g

Ti valves are more forgiving due to the coatings. Either will require a moly stem coating.

+.300 tip are typically steel insery and .250 use lash caps in many apps so be cautious of that spec.

The Xceldyne rep told be the BeCu seats (and moldstar 90, etc) were employed for heat dissipation more than anything. He also advised me to avoid working with the material without a respirator.