I just made a demo test yesterday, found an intresting point.
I bought Darwin A first for a few hours, then i sold it and bought Darwin B, i did that like 2 or 3 times.
So i never had more then 1 Darwin in my "portfolio", instead i was trading Darwins, only 1 at a time.
At the end of the day i got ~10% diversification rebate for 2 Darwins traded, but it never was a real portfolio.
Don't know if this is intended, but it's nice to know in case someone wants to start "trading" Darwins intraday.