Would definitely go with the larger one, considering that you want to go with a 1920x1080 resolution as the maximum. I would always aim everything to fit with the limits of what I have to work with, in your case being a really big resolution size.
A smaller character on a bigger screen resolution would seem awkward, too small compared to the rest of the world; obviously depends on the resolution (i.e a 30x50 character on a 1280x768 resolution would look way too small and hard to follow compared to character let's say double that size, 60x100, on that same resolution).
Incidentally, it also goes the other way around, you don't want your character to be too big on the smallest resolution you have to offer, but I doubt that's going to be a problem.
It also depends on what you're trying to achieve and work with; a smaller character would consequently make the whole world around him look vaster (especially with the resolution of 1920x1080), and would also make your work easier, particularly on animations.
But it also has its downfalls; the amount of detail you can put onto him, and the balance between his size and the max resolution size.
On a lesser note, the objects around the 90% version look somewhat too big compared to him.