Seems to me that at a certain point, maximizing power of the forward stroke is going to cause more yaw in a short solo boat
Maybe. As I said somewhere above, you may need to shorten your stroke if you are in a short, turny boat.
But yaw isn't just a function of the power of the stroke. Say you are stopped in the water. Now take the least powerful stroke you can. What happens? You instantly yaw. The faster you going, the less yaw tendency any given stroke of any power will have. Shortening the stroke will cause less yaw because your paddle will be further forward of the boat's pivot point than with a longer stroke. But then the boat will slow down unless increase your stroke rate.
To me, this is all a hassle, which is why I don't hit & switch in a short, turny canoe. By the time I flip the paddle over to the other side, I can be doing a minor J/C/pitch/Canadian correction to stop the yaw. I save hit & switch for when I'm paddling a longer, harder tracking canoe, particularly when I want to go fast, or upstream, or into the wind.
Even then, hit & switch is a very minority stroke technique for me. I find it boring, inelegant and unaesthetic compared to the rich variety of fluid single-sided corrections that meld into each other automatically when you are experienced, and which can make you go straight unconsciously without some paddle constantly flashing in front of your face. Additionally, if you like to paddle with long or heavy paddles, such as animal tail paddles, rapid tempo hit & switch paddling is klutzy and tiring.
For me. Maybe not for thee.