How small should Kandorians be?

In the silver age, they were always depicted as being about a few inches tall when outside the bottle city of Kandor, despite the fact that the city was much smaller than that.

And in All-Star Superman, despite having the biggest version of the city in a bottle, Kandorians were literary microscopic, being about the same size as red blood cells (so basically the crew from Fantastic Voyage). Although I don’t really like the idea of them being too small to interact with humans, it makes sense given the city’s usual population being somewhere in the millions.

So I ask: how big do you think Kandorians should be? And through extent, how big (or rather, how small) the bottle city of Kandor should be?