That is a question that only you can answer.

I put 10 inch Yaffe Monkey bars on my bike a year ago. They are a huge improvement over stock, but I want more. I was trying to keep them at or behind the fairing which drove my decision. I just ordered new 12 inch yesterday!

Try to sit on some bikes and see what feels best for you.

In my opinion, 10 inch bars would be a waste of money and effort. It’s not much of an increase over stock. I started with 12” bars and ended up swapping them for the 14” bars I should have installed in the first place. I’m not the only person on here that went with the lower of 2 sizes and ended up wishing they had gone higher. Think of it this way. If you stand looking through a tall chain link fence and you grab the fence with both hands for comfort, where are your hands. I would say most people would grab it at or above shoulder height.
Anyway, just something to think about. Everyone has differing opinions on what’s comfortable.

Oh ya, I also find low speed manovering easier with higher bars.