Well, this is very subjective and it is more of a taste. Just in general, when you enlarge more, you present more details, even from the dark areas where little details can be seen before. To human eyes, this may seems less contrasting and less density. To compensate for this, you may have to slightly increase both contrast and density. But again, you just fool your own eyes since you know that two identical prints can look different when presented with two different sizes.