For me, the ideal goal is 200K per year. I would be comfortable reaching that goal with 10 million in the futures account.
In your situation if I had 10m liquid net worth but only wanted to make $200K trading, I you would put 4% of that 10million (400K) into a futures account and look to make 50% on it. You wouldn't even need 400K in there, you could get by with just enough to cover margin plus a buffer on top, and then top up as needed.
The other 9.6 million i would invest in other liquid instruments.

