Some diesels still have flat tappet cams and I still run a zinc additive to help the tappets and cam live longer. The common rail cummins 5.9 engines have very narrow cam lobes and they start eating tappets at around 125k. The zinc additive slowed down the wear process on the ones we service.

I can not help you with your cam choice either. Maybe Tech will see this and he can probably lead you in a good direction.