I tried 1/4, 1/2, 2/3, 1 cup (that was with coconut oil and got a nightmare). The biggest stone I got out was 3cm. across. And that was with 1/4 cup of olive oil!
I think, 1/4 and 1/2 doesn't mean much at all- it depends when liver/gallbladder is ready to expel, not how much you will drink.
It's like you put in your car 10 gallons of gasoline- it will not run faster if you did put 5 gallons...
So the answer is... YES!