Based on how I built my fork, a small band brake was the only thing I could think of.
Using a system like that would be cool, it might even work. But it would be a bit like riding the clutch on a motorcycle I think.
Every trike I've ridden, with exception of the one I posted a pic of tends to pull to the left. That's why it feels like you're going to fall off in turns.
I don't know why they do that, but that's my experience.
The trike kit I have is similar to yours.
The one side uses bolts in between the...