Cylinder head end cap. Old vs New design

[Ronin]

So the V6 and V8 engines have these cylinder head end caps for the cam shafts.

The current design is just a piece of pressed aluminum coated in rubber which gets pushed into the hole. I've had these replaced on my car a year ago and they are leaking straight onto the exahust, so If I'm going to replace them I will probably coat them in sealant too..

The old design for these used in Audi 100 era V6 engines was a machined piece of metal with an o-ring going around it, these are hard to find but still available..

My question is:
Am I better off using the metal cap with an o-ring or the current single piece cap? looking at both designs the one piece rubber coated cap would have a lot more sealing surface (especially coated in sealant) than the o-ring.. but also is a lot more suspectable to temperature and pressure being so thin..
I think VAG just changed and worsened the design cost cutting purposes.

pic for reference: