I am sure of one thing: tightening the head bolts will absolutely not help.
The main reason I am sure of this is that the leak isn't coming between the gasket and the head or the block. Retorquing doesn't help even when it is such. The leak at the front on the 104 motor comes from the compliant seal under the cam housing hardening and not staying with the head gasket as it recedes under the head.
Bosch Master, ASE Master, L1
33 years MB technician