If life could be defined by risk/reward we would all own it
Nobody would still be married if they had a stop loss
I see no hope for bracket traders
Nobody would still be married if they had a stop loss
I see no hope for bracket traders
maybe so, but it would be nice if it was really like that like they tell us in the booksYou need a better, more specific definition of "optimality". What you're possibly looking for is an inflection point, I guess. Until you hit that point, for every incremental increase in risk, your increase in reward is bigger than the previous iteration.

The "optimal" point on that chart would be as far to the left as possible. As your slope turns you are getting less "bang for your buck" than simply leveraging the position.
Consider this:
.1-1.5
.2-2.2 (your idea of optimal)
You can trade your 0.2 and I will trade 2x size at .1. You do not specify a win rate, let's assume it is 50/50.
You lose 0.2 and then make 2.2 and are up 2
I lose .1x2 = .2 then make 1.5x2=3 and am up 2.8
Hence, more optimal.
Is this chart based on any kind of reality?
The "optimal" point on that chart would be as far to the left as possible.
Is this chart based on any kind of reality?
I see, so this is showing diminished aggregate return over a period of time for a large number of trades based on some leverage level proportional to your x?
You might then want to read Ralph Vince's books on optimal f. He is the guy that worked with Larry Williams when he was entering the futures world cup. They were looking at an approach to risk similar to Kelly betting. Their intent was to maximize the odds of winning (max return) in a short-term contest with a small account but the information can be useful in general.