MDG-M implementation on standalone ECC

Hello

My question is regard the implementation approach when implementing MDG on own ECC instance (standalone and not on Productive ECC instance)

1. Implement MDG on ECC using just the ABAP stack of ECC. Use flex mode?

2. Copy existing Material customisations on to the new ECC instance and use Reuse Active area mode?

Which of the above options is recommended? The challenge in first option is that we would need development of existing ECC customizations. In second option, the bringing over of ECC customisations to the new instance.

Thanks

Arvind