Dear Anselm,

Thermal contract dot proofing = Prooferstellung im Thermo-Kontaktraster-Druckverfahren (instead of Prooferstellung you could also write Andruckerstellung or Drucken von Kontrollabzügen)

Thermal plate setting = Einstellung der Thermodruckplatte

Plating = (to give you a definite answer I would neeed more context, however I think it refers either to "Druckplattenerstellung" (Durchformerstellung) or "Druckplattenjustierung" (less likely).

I hope that helps a little

Cheers
Claudia