Placement, page-35

The December 2019 expiry is what will allow the oppies to follow a similar pattern to the heads when trading. Longer the expiry date, the closer the price between the 2 will be. As that expiry date comes closer the price will be reflected in the oppies if they are out of the money.
Oppies can be converted at any time to a full head or just traded as an oppie. You had more liquidity on DDDO yesterday, then the heads, so its not a difficult task.

Oppies may not be for you makattack, with some of the points that worry you but for many people, oppies are a way of more leverage and better return. There is much interest in oppies for various reasons and with such a long expiry on DDDO, you will see it will run with the heads..
All the best with your holdings