24-85 vs 18-105

Background: I use a d200 mainly. Also have d3100. I mainly use a 50mm f/1.4 AI-s. Sometimes a 24 2.8 AIs. Occasionally 80-200 2.8 AFD and occasionally 18-55.

I started looking at the 24-85 AF-D 2.8-4; my thinking is that it's probably pretty good at 50, which I use most, and hits the lenghts I use next most often. But then I started thinking maybe the 18-105 would be a better choice. They are about the same price. The 18-105 would work well on the d3100 (i.e., my wife could use it). The 24-85 is faster and focuses closer, which are important to me, but not most important.

Most important is image quality. The reason I generally use either the 50 or the 24, instead of the 18-55, is I'm not real happy with the 18-55. It's not the resolution so much as the color and contrast. Questions:

1) Is the IQ of the 18-105 equal to the 24-85 in the shared range? Particularly wrt color, contrast, and clarity.

2) Is the IQ of the 18-105 better than the 18-55 in the shared range, wrt the same things?

3) Is there a significant difference in the size & weight? It looks like the 24-85 is shorter and bigger around, but not by much. It's hard to tell without actually holding them though.